Hi,

Just to add to Ricardo's answer: with ChimeraX you can choose the width and height of your image in pixels, then when you insert it into your vector file you can choose the physical size it will have. I don't know about other programs, but at least Inkscape will let you choose any unit to express this size in, including inches.

So, to make sure you comply with the journal's requirements, insert your image in your vector file, resize it and place it where you want it in your final layout, then check its size in inches. Divide the size in pixels you generated from ChimeraX by the size in inches it will end up being scaled to in your figure: you get some number in ppi (pixels per inch, also called dpi for dots per inch). If this number is larger than what the journal wants, you're good to go. If it is smaller, generate the image from ChimeraX again, at a larger size in pixels (or conversely resize it to a smaller size in inches in your figure, but typically you want a specific size in the figure so it makes more sense to increase the size in pixels when saving from ChimeraX than to decrease the size in inches in your figure).

I hope this helps,

Guillaume