I am interested in using a particular figure from the literature, but I do not want to go through the hassle of paying to use a figure. What I am wondering is if I made a similar figure, how easy is it to get in trouble for copyright infringement? If I were to essentially redo the image, it would not be verbatim the same, but very similar depictions would be pulled from the image. As an example, I provided two illustrative examples where the bottom image is an "adapted" version:
The second one is in a published paper as well from a reputable journal, so I am guessing that it should be okay to go about making a similar diagram myself, but again, I wouldn't mind other opinions as too when I might start to tow the line on copyright infringement.