Install any of MightyMike's project ROMs in this thread:
http://forum.ppcgeeks.com/showthread.php?t=101356
NOTE: Each of the three project ROMs is a combination of Winmo 6.5/6.5.3 and Sense 2.1/2.5. Pick which one you want most and flash it. Be sure to run the carrier provisioning built into the ROM before doing anything else after the flash
As far as working picture email, you'll need to do a search for the Sprint MMS fix. It's a big topic... shouldn't be too hard to find
Also, to get back to the standard windows mobile messaging back, you'll need to either install the Zenyee text message fix, or the CMYLXGO text messaging fix. Search for them