The picture automatically adding itself to your gallery is something I have seen on the LG Esteem, the LG Connect and now the LG Motion. I have noticed that some apps just store pics in your gallery. Specially the Bejewled app. So I know what your talking about there. It is not a phone issue. So just delete them.
Like others have said, the system uses up your RAM (about 290 of your 1GB). So you should have about 710 RAM left at your disposal.
The image resizing issue, is not a phone issue. Try different wallpaper apps.
If you are having Wifi issues, then try freezing the MetroPCS Wifi App, and then reconnect your wifi. If there is no improvement, then it must be your router. If it is not your router, then get your phone replaced.
For your animation issue, there is an animation option on your phone settings, make sure you have the "All animations" checked and reboot. If there is no improvement then have your phone replaced.
Hopefully this helps you a bit. Cheers!