Tried to submit the Tiger I again but got this error message:
Welcome to new skins validation page.
Object Name: tiger1 Verified
Skin Information: Verified
Skin Name: s. Pz Abt 503 by Greebo Verified
Skin Files Verification
All Required files: Submitted
File upload names: Verified
File upload bit count, type, or pixel size: Failed Verification
PZ6TRED_E.bmp is smaller than the default allowed pixel size width (1024).
PZ6TRED_E.bmp is smaller than the default allowed pixel size height (1024).
So I tried a Jagdpanther, the only other AH III-format GV skin with track files I have done. This one uploaded successfully so the Tiger issue may be specific to that shape and not related to all GVs.
I also successfully submitted the Camel skin and a Ki-61 skin. My Ki-61 E, P and S files show a size of 4,195,382 bytes however.