This app gives you the power to annotate over any photo. You can simply make notes on them or even sign your name to forms.
RH: Everyone has favorites and for annotating over photos, this is mine. There is a "lite" version which is good but the fee version gives you the opportunity to write as many individual notes as you want. The writing is very smooth which is what I look for in a writing app. I can take a form from the office and import the image here and sign away as well as fill in boxes. Then, I can simply email it back to the office without leaving my desk. What I really like is that it makes my poor penmanship look pretty good.
Here are a couple of samples of photos annotated using A+ Signature. Wish I really visited Hawaii.
You may import any photo such as a form, sign, and send it. (Using your iPad, snap a screen shot of the form, save it to your photos, then import it to A+ Signature.)