Try to reduce the picture side/pixils. Pics are suppose to be between 100KB to 600KB..... if your pics are more than 1MB then your picture may be to large.
320-by-240-pixel resolution at 204 pixels per inch (4Th Gen)
240-by-432-pixel resolution at 202 pixels per inch (7th Gen)
240-by-376-pixel resolution at 204 pixels per inch (5th Gen)
Hope this helps.