John Kitchin has a very nice post in which he presents at bit of Elisp that enables us to drag and drop images into an Org buffer. The code is short and easy to understand. I just cut it out of his post, pasted it into my
init.el, and evaluated it. After that I could drag and drop just as in his video demonstration. The only problem I had was with the 【Ctrl】 drag and drop. When dragging from the Finder, 【Ctrl】 clicking on an item brings up a menu. What you have to do is drag it over to the Org buffer and then press control before you release the mouse button.
Kitchin's code was developed on a Mac and according to the comments has some problems with Linux machines. If you experience any trouble, you might want to try abo-abo's drag and drop solution. If you're interested, check out his demonstration video.
I really liked that when he first demonstrated it but, as I recall, there was some indication that it wouldn't work on a Mac so I never tried it. After reading Kitchin's post, I downloaded and tried abo-abo's org-download to see how it compared to Kitchin's solution.
I had a couple of glitches but to be fair I didn't do more than a cursory trial. I could have probably resolved my problems with a bit of code reading. On the other hand, abo-abo's solution allows you to grab images from Web pages while Kitchin's code works only with images in the file system. Between the two solutions, you should find one that works for you and meets your needs.