I did the same thing last year. I think I bought 8" frames.... Whatever size they were I looked in the docs and it gave the pixel count. Let's say these were 800 x 640. So whatever size your image is, it will be remapped to your frame's resolution when it is displayed. So even if you have a 10MB image, it will only display as many pixels as the frame has.

So I have downloaded and use PICASA2 from Google. It is a free electronic picture library application. It has a function to make a "gift CD" of pictures. In the creation of the CD it offers a chance to resize your pictures. I chose the 800 x 640 resolution and the pictures are now all about 500Kb and not 6MB in size. I had an old 512MB camera memory card and it would fit nearly 1000 pictures on it.

I'm sure there are other sizing options or applications, but making them fit the resolution of your frame allows you to get many more pictures stored on a memory card. Good luck!

Chuck