[282883392]

How? "Screenshot" is used correctly by the OP.

For reference:

  screenshot
    (verb) an image of the data displayed on the screen of a computer or mobile device.

[mkl]

Their usage does not match that definition. When recognising writing, they are recognising an image of the page, not an image of what was on the screen at some other point.

Also, your definition describes a noun but claims it's a verb.

[282883392]

The promotional material shows the application interpreting a screenshot of an equation, not handwriting.

I also meant noun, not verb. Thanks.