add a "before/after on all the image" option

**Description** Is your suggestion related to a problem? Please describe. I like seeing the "before/after" on all the image but there is only a "toggle" option. **Solution** Describe the solution you'd like to see. a new button "before/after" that deactivates temporarily all the modifications made on an image (but not only on half of it). Click back on it when you want to reactivate everything. **Alternatives** Describe alternatives you've considered. [ A clear and concise description of alternative solutions you have tried or considered.] **Additional Context** Add any other context about the suggestion here. [ Anything else you want to add goes here ]