I recommend you to use zip file instead of plain png files. They are good but when their amount is lesser or equal to three
Viewing post in GB "ACE!" Asset Pack jam comments
1. Didn't notice it sorry.
2. When you have zip file, I don't think that users need separate png's but ok
3. It is normal for compression. You need to store some additional metadata to be able to uncompress so if you compress something small and non repetitive, the size of metadata can be larger than you can save with compression...