I've used a resizing program to resize my image to the requisite 100 by 155 pixel dimensions for the banner image; but when I upload it I get an error message saying there's something wrong with the dimensions. The image I'm uploading is a stock photo I've purchased and have full rights to, meaning it's not home made. Any idea what else the problem could be. The program im using is pretty old and standard. Is there a specific one that can be recommended that is straightforward and won't give me an error on the facebook details page?
Sorry for misunderstanding,
Check out these instructions here: https://developers.facebook.com/docs/guides/appcenter/#uploading
Especially those:
If your problem persist, Try another program. Personally, I use Adobe photoshop (Actions) to generate all graphics for my facebook apps, also there's tons of other programs that can help.