"Yes", I tell visa applicants again and again, "you do need more photos
even though you already have a passport if you want a visa". I have even offered to cut photos out of people's passports for them. This is not difficult people: provide a passport photograph. But do not be like the person who provided a photograph of his passport instead of a passport photograph!
Almost
every country wants at least one standard passport-style colour photo
attached to each visa application. The general rules are the image
should be passport-photo size, usually colour, full face, head on, no
hats and usually no glasses, never sunglasses, white or grey background,
and taken recently. If you wear religious or cultural headcoverings,
you will have to make certain of the requirements. All photos must be
identical.
Some embassies require the photographers stamp and date on
the back, but most do not. Most embassies want one or two, but a handful
of embassies demand four! The good news is these are available almost
everywhere now, including many pharmacies. And it is always best to have
extra copies of both the photos and the visa application forms
(filled-in) with you during your travels in case some nasty border guard
insists on more paperwork.