What are the necessary and recommended practices to cite a published picture of experimental result? I want to make a direct comparison between my simulation result and a published picture of other people's experimental result.

There are a lot of morphological features of similarity, which are difficult to describe by words only, and it should be better to simultaneously put the two results in my paper instead of suggesting readers to find that cited picture themselves, so I want to make the comparison by putting their picture and my numerical result side-by-side.

Specifically,


The picture of their experimental result was an optical photograph in black and white, while my simulation result was colorized;
My target journal is different from that of the cited paper.


I did find a similar example for my reference and thus I kind of doubt that this is not a usual practice in paper writing. Could anybody suggest me what should do before I prepare such a figure and submit my paper? Thank you!
If the source is an open-access paper under a creative commons license, it's easy - copy the figure and attribute the source and license.

If not... most publishers have a system for this. The STM Association, which covers the majority of mainstream scientific publishers, has a set of guidelines for permission between its members, setting out what is reasonable to reprint, and importantly has a general reciprocal agreement that they will honour each others requests without charge. This covers both books and journals, broadly speaking.

The STM list has the appropriate links per publisher. Some have a blanket permission, others require a bit of paperwork. For example -


a figure copied from a Portland Press-published paper does not require permission to be reused;
a figure copied from a Royal Society of Chemistry published paper does require permission, but this permission will be automatically granted at no cost if you fill in the online form correctly.


You do not need to do this before submission (at least, not in the cases I've dealt with) - it comes after acceptance when you know where it will be published and you're sorting out the details.

In the majority of cases, because copyright is transferred to the publisher (or they are given a very broad license to authorise republication) you do not need to approach the author. However, you might want to anyway.

Firstly, it's polite, and I'm sure they'd be pleased to know you're publishing something building on their work. :-)

Secondly, and potentially more importantly, permission to republish doesn't mean that the publisher will send you the files. You might need to get hold of a copy of the master images rather than the version put out by the first journal, in which case you'll have to speak nicely to the original author and hope they can find them...