(Concurring in the judgment).
I agree that the judgment should be vacated, but I would not hold that the government must present evidence in addition to the image itself to prove that the picture depicts an actual child and not a virtual image.10
I.
The law in this circuit has been that a trier of fact, without the assistance of an expert or other evidence, can discern between an actual and virtual image of child pornography. See United States v. Nolan, 818 F.2d 1015, 1017-19 (1st Cir.1987). In Nolan, a pre 1996 Child Pornography Prevention Act (“CPPA”) prosecution, the defendant challenged his conviction on the grounds that the government had failed to prove that the pornographic pictures at issue depicted actual children. Id. at 1017. The defendant argued that the pictures were insufficient evidence on this issue because the government failed to present expert testimony that the pictures were not generated through computer imaging or similar methods. Id. We rejected this argument, concluding that “ordinary people in today’s society are quite accustomed to seeing photographs and distinguishing *67them from other forms of visual representations.” Id.
As I read today’s decision, we overrule Nolan because “the vast technological revolution underway since {Nolan was decided] has made undeniable the fact that sexually explicit images portraying children can be produced through artificial means.” Ante at 65. There can be no doubt that we have undergone a technological revolution since Nolan. One need only turn on a computer, attend a movie, or view one of the latest video games to understand that we live in a digital age in which virtual images look more and more real. One certainly can understand the majority’s concern that this same technology could be used to produce realistic virtual pornography.
However, I think the question we resolve here should not be whether technology has improved greatly since Nolan. The relevant question in this case, involving images created almost a decade or longer ago, should be whether the available technology had progressed to such an extent that we can never (and specifically in this case) trust lay people, unaided by experts or other evidence, to differentiate between the real and the virtual. I would adhere to Nolan and to what appear to be all of the other relevant authorities to conclude that ordinarily fact finders can continue to distinguish between real and virtual images of child pornography based solely on the presentation of the images.11
It is true that in passing the 1996 amendment to the CPPA, Congress appears to have taken the view that there are instances in which lay people are no longer able to distinguish between the real and the virtual. As the Senate report put it:
New and increasingly less complex technology and expensive photographic computer imaging technologies make it possible for individuals to produce on home computers visual depictions of children engaging in sexually explicit conduct that are virtually indistinguishable from retouched photographic images of actual children engaging in sexually explicit conduct.
S. Rep. 104-358 (emphasis supplied).
The Supreme Court, however, does not agree. In Free Speech Coalition, the government claimed that, under current technology, “virtual images [can be created that are] indistinguishable from real ones.” 535 U.S. at 1404-05, 122 S.Ct. 1751. The Court found this “hypothesis [to be] somewhat implausible.” It reasoned, “[I]f virtual images were identical to illegal child pornography, the illegal images would be driven from the market by the indistinguishable substitutes. Few pornographers would risk prosecution by abusing real children if fictional, computerized images would suffice.” Id. at 254, 122 S.Ct. 1751.12 The import of this statement is *68that the typical consumer of child pornography can differentiate between real and virtual depictions of child pornography. Presumably, if the average child pornography consumer can make such a determination, so can a judge or juror.
In the wake of Free Speech Coalition, every court to have considered the question has determined that the presentation of the pictures alone constitutes sufficient evidence for determining that an actual child is depicted in the pornographic image. See United States v. Slanina, 359 F.3d 356, 357 (5th Cir.2004) (per curiam) (“[T]he Government was not required to present any additional evidence or expert testimony to meet its burden of proof to show that the image downloaded by [the defendant] depicted real children and not virtual children.”); United States v. Kimler, 335 F.3d 1132, 1142 (10th Cir.2003) (“Juries are still capable of distinguishing between real and virtual images.”); United States v. Deaton, 328 F.3d 454, 455 (8th Cir.2003) (upholding jury’s conclusion that pictures depicted actual children “where the images themselves were the only evidence the government presented on the subject”); United States v. Hall, 312 F.3d 1250, 1260 (11th Cir.2002) (concluding, after review of pictures, that “no reasonable jury could have found that the images were virtual children created by computer technology as opposed to actual children”); United States v. Fuller, 77 Fed.Appx. 371, 379 (6th Cir.2003) (unpublished disposition) (citing Deaton for proposition that “jury’s conclusion that real children were depicted may be upheld even when the only evidence offered was the images themselves”); see also United States v. Brinkley, 2003 WL 22495757, at *8 (A.F.Ct.Crim.App. Oct.31, 2003) (citing Kimler for proposition that “Free Speech Coalition does not require either direct evidence of the identity of the children in the images or expert testimony that the images are of real children rather than computer generated virtual images”) (unpublished disposition); People v. Normand, 345 Ill.App.3d 736, 281 Ill.Dec. 478, 803 N.E.2d 1099, 1103 (2004) (holding that under Illinois child pornography statute “the trier of fact may make a determination as to how an image was produced from the image itself.”); Commonwealth v. Simone, 2003 WL 22994238, at *22-23 (Va. Cir. Ct. Oct.10, 2003) (holding that under Virginia child pornography statute “the Commonwealth may seek to rely upon the images themselves without the necessity for expert opinion” to prove that pictures depict images of actual children). In my view, there is nothing about this case that provides a substantial reason to decline to follow the Supreme Court’s guidance on this issue and to reject the holdings of our companion courts that evidence in addition to the image itself is not required to prove that the pornographic picture depicts an actual child.
The majority opinion suggests that testimony by a computer graphics expert or evidence identifying the depicted child could satisfy the additional burden that the government must now meet to prove that the picture at issue shows a real child. Ante at 65 n. 6. After Free Speech Coalition, defendants will certainly argue that the government has failed to prove beyond a reasonable doubt that the pictures are of real children. And, in light of evolving technology, triers of fact may be more inclined to accept such arguments if the government relies on only the pictures as evidence. Nevertheless, it is one thing to *69acknowledge that the government could benefit from introducing additional evidence and quite another to insist that the government introduce such evidence in every case regardless of the circumstances. I would not require that, as a general rule, the government must introduce additional evidence to meet its burden of proving that the pictures at issue depict actual children.
II.
Although I believe that there was sufficient evidence to sustain Hilton’s conviction based on the government’s presentation of the images in his possession, I nevertheless agree that Hilton’s conviction must be vacated.
Because - Hilton’s trial occurred before Free Speech Coalition, the government was not required to prove that the pictures at issue depicted actual children to gain a conviction. As a result, the trier of fact did not find that the pictures in Hilton’s possession depicted actual children as is required for a valid conviction. See ante at 63 (stating that parties agree that Free Speech Coalition applies retroactively to Hilton’s conviction). The failure of the trier of fact to find every element of a crime (even though sufficient evidence on the element was presented at trial) is a constitutional error that sometimes requires reversal. See United States v. Gaudin, 515 U.S. 506, 511, 115 S.Ct. 2310, 132 L.Ed.2d 444 (1995).
However, the failure of the fact finder to find every element of a crime does not mandate reversal in all cases. Errors of this sort are susceptible to harmless error review. Mitchell v. Esparza, — U.S. —, —, 124 S.Ct. 7, 11, 157 L.Ed.2d 263 (2003) (per curiam); Neder v. United States, 527 U.S. 1, 19, 119 S.Ct. 1827, 144 L.Ed.2d 35 (1999); United States v. Raheman-Fazal, 355 F.3d 40, 47 (1st Cir.2004). Indeed, some courts have upheld pre Free Speech Coalition CPPA convictions, despite the fact finder’s failure to find that the pictures depicted actual children. See United States v. Wolk, 337 F.3d 997, 1004-05 (8th Cir.2003) (upholding CPPA conviction, under plain error review, because strong evidence demonstrated that pictures depicted actual children; accordingly, lack of jury finding on “actual child element” did not affect defendant’s substantial rights); Hall, 312 F.3d at 1260 (similar).13
Had the government asserted that the error here was harmless, I would have seriously considered its argument. But the government, the appellant in this case, has chosen not to do so. The argument is therefore forfeit. See Plumley v. Southern Container, Inc., 303 F.3d 364, 372 n. 7 (1st Cir.2002).
Furthermore, the state of the record does not permit us to find harmless error sua sponte. See United States v. Rose, 104 F.3d 1408, 1414-15 (1st Cir.1997) (stating that in some cases court may raise harmless error sua sponte). The trial transcript is not part of the appellate record, which makes conducting a harmless error review all the more difficult.14 See id. at 1415. While the record before us *70includes the pictures in Hilton’s possession, I cannot tell what other evidence, if any, would support a harmless error conclusion. Indeed, I cannot even discern how the pictures were introduced at trial or what evidence was given to the trier of fact about them by either party. While the pictures alone can constitute evidence sufficient to sustain a CPPA conviction, I am not prepared to say, on this incomplete record and without argument from the parties, that they are enough to conclude that the fact finder’s failure to find that the images in Hilton’s possession were of actual children was a harmless error.
. The issue here concerns only the evidence necessary to distinguish between actual and virtual images of child pornography. Eviden-tiary issues concerning "morphed images” of child pornography ie.g., images that combine a child and adult body to make one image) are not implicated because possession of such images remains illegal under the CPPA. See Ashcroft v. Free Speech Coalition, 535 U.S. 234, 242 at n. 8, 122 S.Ct. 1389, 152 L.Ed.2d 403 (2002).
. This is not to say the majority's concerns are off base. Indeed, as a matter of the reliability of evidence, it is not clear where the logical stopping point for the majority's concerns is, and the time may come when the rule it today establishes for this circuit will become prevalent. For now, I would leave the issue to sound trial management by the district courts.
. The dissenting Justices accepted the government’s argument that virtual images could be created that are indistinguishable from real ones. See Free Speech Coalition, 535 U.S. at 264, 122 S.Ct. 1389 (O'Connor, J„ dissenting); 535 U.S. at 268-69, 122 S.Ct. 1389 (Rehnquist, C.J., dissenting). In addition to the majority opinion, Justice Thomas, stated that while technology may advance to the point that indistinguishable virtual images could be created, the government failed to demonstrate that this advancement had already occurred. Id. at 259-60, 122 S.Ct. 1389 (Thomas, J., concurring in the judg*68ment). Thus, the various Free Speech Coalition opinions indicate that the issue of whether truly indistinguishable virtual images of child pornography can be created using modem technology was considered by all the Justices and rejected by a majority.
. These cases were decided under the "affecting substantial rights” prong of the plain error analysis under Fed.R.Crim.P. 52(b). Such analysis is essentially the same as a harmless error review except that the defendant, not the government, bears the burden of proof under Rule 52(b). See United States v. Soto-Beníquez, 356 F.3d 1, 49 (1st Cir.2004); United States v. Ramírez-Burgos, 313 F.3d 23, 29 (1st Cir.2002).
. Although the government’s brief cites to the trial transcript, the docket indicates that the only transcripts filed in this court were of a bail hearing held on June 5, 2003 and a motion hearing held on June 9, 2003.