It depends on the copyright of the original image. If it is Cretive Commons, check the type of CC that the figure has. Some of then alows edition, some others, not.
thank you for your valuable opinions Ms.Pires and Mr.Sánchez.
Please see the following opinion:
Do I need permission if I alter a figure?
The important issue in determining whether permission is needed for an altered figure is the amount of alteration. The change must be substantial if you want to avoid the legal requirement to obtain permissions. What constitutes "substantial" change is a murky legal area. Changing straight lines to arrows, relabeling a figure with letters instead of numbers, or reordering columns in a table does not constitute substantial change and can distort the meaning of the original material. The best approach for avoiding permission issues is to use original materials wherever possible.