Typically from a mobile development standpoint there is never a "one size fits all" solution. There are many different screen sizes and hardware configurations. In order to combat this many developers will generate -as mentioned previously, Sprite Sheets. Using this method the application only has to load one image vs -in your case hundreds. Image loaders take quite a while connecting to a memory address to initiate a texture upload to the GPU -I can't even image how slow it must be for that many assets.
This texture packer is phenomenal, and also aides with another feature many dev's incorporate. Asset Densities. Wherein the iPhone 3Gs a dev will load a set of sprite sheets developed for smaller screen sizes, a larger sprite sheet with twice the sized assets will load for a tablet or some of the higher end devices. This method will not only solve your memory issues but make your application look much better over a broader range of devices.
Here is a link to the Starling Wiki on multi-resolution development.
Of all the changes you can make to a project "for the better" the ones mentioned above are very high on the list.