I do something like this (upload photo) to form, but from Adobe LiveCycle.
Salah is talking about something different than you're using.
PDF created with InDesign and Acrobat Pro isn't capable of supporting uploading images into a form.
Salah may be correct, but he's talking about a different product—LiveCycle Designer. Before Acrobat Pro XI, LifeCycle Designer was included with Acrobat Pro—but ONLY for Windows, not for the Mac. It created what's sometimes called XML PDF.
However, it's now a separate product (not included with Acrobat XI), it's still not supported on a Mac, and it doesn't work when viewed on mobile PDF readers like Reader for iOS.
Salah may be correct, but he's talking about a different product—LiveCycle Designer.
Steve, you are right.
I do the form on indesign CS6, and after export to interactive pdf i add Insert Image button at LiveCycle Designer.