*1 The defendant, Bryon L. Banas, appeals from his conviction of larceny under $250. The defendant argues that it was error to admit a picture from the defendant's Facebook page and that there was insufficient evidence to support the verdict. We affirm.

Discussion. Admission of Facebook picture. The defendant argues that it was error to admit a picture of shoes from the defendant's Facebook page because it was not properly authenticated as being posted by the defendant. We agree it was error but conclude it was not prejudicial.

Authentication is a “condition precedent to admissibility” that requires that the proponent provide “evidence sufficient, if believed, to convince the jury by a preponderance of the evidence that the item in question is what the proponent claims it to be.” Commonwealth v. Purdy, 459 Mass. 442, 447 (2011). In Commonwealth v. Williams, 456 Mass. 857, 869 (2010), the Court held that evidence that a message was from an individual's Web page was not sufficient to authenticate that the individual wrote the message. Evidence of additional confirming circumstances is needed to authenticate the message, which could include “how secure such a Web page is, who can access a Myspace Web page, whether codes are needed for such access, etc.” Ibid. See also Commonwealth v. Purdy, 459 Mass. at 450.[1]Here, Nalepinski testified that he was Facebook friends with the defendant, logged onto defendant's page, saw the picture, and printed it. This was not sufficient to authenticate that the post was made by the defendant. It was error to admit the picture. This issue was preserved for appeal,[2] so we must determine whether the error was prejudicial. See Commonwealth v. Urban, 450 Mass. 608, 614 (2008), citing Commonwealth v. Flebotte, 417 Mass. 348, 353 (1994). An error is nonprejudicial only if the court can say “with fair assurance, after pondering all that happened without stripping the erroneous action from the whole, that the judgment was not substantially swayed by the error.” Commonwealth v. Flebotte, supra, quoting from Commonwealth v. Peruzzi, 15 Mass.App.Ct. 437, 445 (1983). This evidence was not particularly probative, since it only weakly supports the inference that the defendant purchased new shoes soon after the victim's money was stolen. In addition, the defendant himself mentioned the new sneakers in his opening argument before the Commonwealth made any attempt to bring the picture to the court's attention. Finally, there was much stronger circumstantial evidence that the defendant stole the money.[3] Therefore, the finding of guilt was not substantially swayed by this error.

Sufficiency of the evidence. Evidence is sufficient to withstand a motion for a required finding of not guilty if, “after viewing the evidence in the light most favorable to the prosecution, any rational trier of fact could have found the essential elements of the crime beyond a reasonable doubt.” See Commonwealth v. Latimore, 378 Mass. 671, 676–678 (1979), quoting from Jackson v. Virginia, 443 U.S. 307, 318–319 (1979). “A conviction may rest entirely on circumstantial evidence, but no essential element may rest on surmise, conjecture or guesswork.” Commonwealth v. Jones, 59 Mass.App.Ct. 157, 160 (2003), citing Commonwealth v. Donovan, 395 Mass. 20, 25 (1985). However, “[a]n inference drawn from circumstantial evidence ‘need only be reasonable and possible; it need not be necessary or inescapable.’ “ Commonwealth v. Gilbert, 423 Mass. 863, 868 (1996), quoting from Commonwealth v. Beckett,373 Mass. 329, 341 (1977).

*2 The defendant primarily argues that the evidence is insufficient because the circumstantial evidence equally supports an inference that Nalepinski stole the money.[4] See Berry v. Commonwealth, 393 Mass. 793, 796 (1985) ( “When the evidence tends equally to sustain either of two inconsistent propositions, neither of them can be said to have been established by legitimate proof”). Although the evidence does support the conclusion that only the complainant, Nalepinski, and the defendant had knowledge of where the money was and the opportunity to take the money, it does not equally support an inference that Nalepinski stole the money. As the Commonwealth argues in it's brief on pages 11–12, there was evidence that Nalepinski and the complainant were roommates who had no history of fighting about money, the complainant loaned Nalepinski money on a regular basis, the complainant and Nalepinski split rent payments, and Nalepinski was employed at the time. Further, there was evidence that the defendant was seen in the complainant's room alone right after he learned where the money was hidden, the money was missing shortly thereafter, and the defendant was unemployed and homeless at the time of the incident. Contrary to the defendant's assertion, this is not a case where the jury were presented with evidence that two parties were equally disposed to commit the crime. See Commonwealth v. Torres, 442 Mass. 554, 564 (2004) (where two individuals had the opportunity to commit the crime, the question for analysis of the sufficiency of the evidence is “whether there was ... evidence pointing more strongly in the direction of the defendant such that the jury could rationally infer that he was the principal”). The evidence here was sufficient.