Performance claim

Any assertion about results, whether it appears as a percentage, a screenshot, an equity curve or a description of a run of positions. Where it is made by or on behalf of a licensed firm it is a regulated document and the conduct rules apply in full: the required risk warning has to be present, the basis of the figure has to be stated, and a claim the firm cannot evidence is prohibited whether or not anyone relied on it. The medium makes no difference to any of that.

A screenshot is the weakest form of evidence in common use, and its weakness is structural rather than a matter of suspicion. There is no way to establish from an image that the account exists, that the person posting it holds it, that the entries were placed at the times displayed, or what the rest of the record contained. An account statement is a different class of object, because it is issued by the firm that holds the account, in the name of the account holder, and it covers a period rather than a selection from one.

The property that undoes most published records needs no dishonesty at all. What is posted is a selection from a pool of outcomes made by the person publishing it, and the selection is not random: the good ones are posted, the bad ones are deleted, were never posted, or belong to people who went quiet. That is survivorship bias operating on a feed, and it is why a record without an independently produced statement covering a stated period carries no information about a method.