For animating characters or objects in simple 2d games for example you may have 10, 20, or more images displayed at a time. Many of the same image which are usually pretty small (<50kb).
In my nonogram app for example to there can be upto 1440 images for the largest grid but they all point to a maximum of 16 different images all less than 1kb.
There doesn't appear to be a performance hit unless I load an image for each separately even though they will never user more than 1.5mb of memory.
If I have the images point to bitmaps already in memory then no problems.
It would appear that I answered my own question.