Regarding the donkey head:
The Romans at those times saw Christianity as a weird Jewish cult, and often said that Jews worshipped donkeys. It ranged from a weird taunt to conspiracy theories, like "Jews sacrifice foreigners to a golden donkey head".
The Romans got this "Jews vs. donkeys" association from the Egyptians. The Egyptians did it towards foreigners in general - because the evil god Seth was associated with both foreigners and donkeys.
In turn, Seth likely got donkeys as one of its aspects because of the Hittites. There are multiple explanations on why this happened. Perhaps it has to do with Hittite bioweapons? I'm not shitting on you, the Hittites used animals infected with The Hand of Nergal (likely rabbit fever) against their enemies. Another possibility is that the Hittites themselves worshipped donkeys.
Either way, donkeys were a big deal for the Hittites, who likely used them in their everyday lives for cargo transportation. Not surprising once you remember the Hittites were Indo-Europeans, and the Indo-European mythology is filled to the brine with reference to equines, twin horse-riding heroes, so goes on.
Indo-Europeans like the Romans. Who were big fans of horses. And donkeys. To the point that they're the ones responsible for spreading an otherwise African animal across Europe.
Conclusion: if the Romans had tomatoes, they should be throwing them at the mirror, not at the Jews. The donkey worshipers the Romans ridiculed were nobody but the Romans themselves!