Could anyone create a working spider / scorpion unit?

[Erenussocrates]

Scouring the topics in the past, I did stumble across spider and scorpion sprite sheets as I've attached below. Though no matter what I tried, I couldn't get a working unit for these two, as the image seems to be too tiny to be working for the unit, and when I tried to resize it to -say- a footman's dimensions, it didn't work either. The animation shouldn't be a problem, but the game was always giving error regarding the image size of the unit.

Was anyone able to create working units using these? And could anyone help me please?