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Mostly I write under them where I got them from instead of citations.
A few are from wikipedia or NASA, that are creative common licensed.

It's easier to source them for others if you have links or something to the images. After all use of unlicensed images can end up getting steemit in trouble (lawsuit wise) and that would be bad for all of us. Not that I would expect anything to happen but safe practices are generally better and alleviate any concerns. Cheers!

I always provide links to all source material for any images I include in my own posts, so I know what a pain it is first hand...

That is great advice! Thank you very much!
I will see that I practice propper sourcing in further articles.
Probably better to get used to it anyway.

Awesome, thanks for understanding! You rock!