Insect and Spider Identification: Insect or disease?, 4 by bluemerle

bluemerle wrote:
Whatever these things are, they are multiplying. They're now on my tomato plants as well as my bell peppers.
I started noticing them about 3 weeks ago as tiny raised 'bumps'. I don't know if they're related or not but have found them on the same leaves.
When you hold the leave up to the sun, you can see right through them.
I've showed both sides of the leaves, they're identical- same "thing" all the way through.
In the 1st pic there's a fly(?), 2nd pic shows one of those "bumps", 3rd pic is top of leaf, 4th pic is underside of leaf, and last one is what it looks like when you hold the leaf up to the light. Shows right through! ???

Please give me a clue FlapDoodle, if at all possible. Should I post this to Garden pests & diseases, too?

Thanks, Diane