Frontiers accepts only JPEG, TIF and TIFF for figure submission. TIFF (TIF) files should be saved using LZW compression or any other non-lossy compression method.
Figures should be uploaded separately during the submission process, unless you are submitting LaTeX files. You can then include your figures directly in the manuscript. The original files of the figures, preferably in EPS format, might be requested during production stage (post acceptance).