This is for 8.1, but should work for 8.2 It provides libpng.so.2
http://rpmfind.net//linux/RPM/mandrake/upd....2mdk.i586.html
I used kshowmail in Mandrake 8.2 with no problems. Also, the kshowmail I pointed you to is v2.2.3, which is the version I used in MDK 8.2, not v2.0
http://unc.dl.sourceforge.net/sourceforge/...il-2.2.3.tar.gz
If you can't or don't want to compile, the rpm on your 8.2 CD should work fine after you install libpng2.