(Answers from tumblr users would be great) could i edit & post a pic i found online if i keep the source?

[What]

I really want to start a pale, pastel blog but the problem i always have with those blogs (lots of different blog types actually) is that theyre notorious for promo spam, discrediting OPs, removing sources, self-promoting on reblogs, etc. but most importantly, reposting pictures that they didnt take/edit and not putting the source as the original artist!!! it makes me so mad! but i really love the style of these blogs and i want to start one.

my plan is to edit and post whatever photos i find online (and yes, i will also of course be posting my own photos that i took myself. im just not much of a photographer which is why i want to have a mix of my own photos and random ones that i find online...) but i will ALWAYS ALWAYS ALWAYS put the source AND a click-through link on the image that links to the source. if i cant find a source, im not posting that picture. i refuse to, im studying graphic design right now in college and plagiarizing someone else's artwork goes against my principles, but im not sure if what im asking to do is considered plagiarism or not since im making my main priority to give credit where its due and all...

im obviously not doing this if its a bad idea so i want to know what other people think...
(I hope i explained this well-enough so you guys know what i mean)
oh also, i plan on adding a disclaimer to the blog desription something along the lines of "if any of the pictures belong to you or someone you know, tell me and ill remove them or fix the source" in case i do mess up the source and dont put the right person or something

[Sydney]

Yeah, that sounds fine! Just be sure to comply if someone asks you delete something.

[Doraa Weasleyy]

It sounds good, just as long as you always contact the person who owns the photo and ask for their permission to edit it. If you have their permission, you can go ahead, as long as you remember to link back to the source.
I would also add a disclaimer saying "photos do not belong to me unless stated", just so people know.