The photo specs are instructions for the photographer that tell the size the photos you submit with the application have to be, and where the image in the photo has to be, etc. Inland ap photo specs are in the Applicant's Guide. For outland aps, they're in the Region Specific forms.
Don't attach the photo to the application - they'll be a specific number you need to include, depending on which country you're from - and then you include the photos in a separate envelope paperclipped to the application forms.