Reducing images size to 600x600 px and the number of frames to 50 you can save ~330 MB!
If memory optimisation is important, I'd recommend going a little under a power-of-two size - in this case 500x500, as it is a little under 512. The reason for this is the images are packed on to spritesheets that are a power-of-two size (2048x2048 by default) with a couple of pixels padding. Images just under a power-of-two size pack much more efficiently on to spritesheets, as more of them can fit on a single sheet. For example a 600x600 image can only fit 9 times on a 2048x2048 spritesheet (3 in each direction), but a 500x500 image can fit 16 times on a 2048x2048 spritesheet (4 in each direction).