multiple problems editing a gif with imageready to post on tumblr

[Katzen Jammer]

the original file (1.7 mb) is 400x300 pixels and 120 frames



after making the background transparent, reducing the file size, color, and adding lossy (to 999 kb) and trying a few different photo hosting sites and different versions of the file they all do this layering thing once online, but in imageready it's still plays like normal



also when i try posting it on tumblr the bigger file won't work (even tho they say max size is 10 mb!?) and the smaller one turns into a still with a black background

why do they play like normal (even in the optimized window) but once online they mess up? too many frames?

i literally spent like 5 hours trying to make it work last night i'm so frustratedddd

any suggestions??? thankyou!