I am writing a thesis for my Final Year Project.
I had read a lot of journals and books and articles regarding the project.
Now, I found that some pictures are very useful in illustrating my explanation in the thesis, especially in the part of the "Litreature Review".
I think it's not so worth for scientists to design all these pictures every time they are going to publish their articles. If there is the existence of the desired pictures in other journals, why not use these pictures? If they have the time to design the pictuers again, why not use the time to think about the other constructive academic things? I admit that re-designing the pictures can refine the pictures to better quality. But I don't think it's necessary all the time. If the pictures come to be unneccessary to be re-designed, I do think that it's more constructive to adapt the pictures from other sources.
Therefore, here comes my question, should I get permission from the authors for the usage of their pictures? If yes, how can I do that?