I recently submitted my first paper to a journal and had some trouble with the figures I uploaded. Specifically, the journal required vector graphics figures to be exported at 1200dpi, grayscale at 600dpi and coloured at 300dpi and I could choose between tiff and eps formats. The problem I faced was that there was an upload limit of 30MBs and I had to submit each figure separately. Keeping the dpi guidelines produced images that had a total size more than 200MBs and the only way I could upload them was by exporting them to 200dpi. Has anyone faced a similar issue and if so, how did you solve it?
The upload limit is clearly a stricter requirement than the image resolution threshold since you can't submit a paper over that size. As you have done, I suspect most people would compress the images to meet the file limit.