How many pixels in a 8x11?
Pixels are a measurement of the resolution of an image. For
example, old laser printers used to print in 300x300 pixels per
inch, then came 600x600 prints. I'm sure you're asking "Why are you
talking about laser printers when I asked about pictures?" Because
the premise is the same. An image that is 1 inch by 1 inch that use
the 600x600 resolution would have a file size roughly twice that of
a 300x300 resolution.
All of that to tell you that no one can really tell you, you
will have to find the resolution of the image, find out how many
pixels are in a square inch of that resolution, then multiple it by
the size image you have.