If for example I change (voluntary or by mistake) the sharpen or the quality of the JPG into "Settings --> Images", then even if I close the X to close the box or I do not click on the "Accept" button, these changes are done and the consequence is the generation of all the images and then if I upload a full upload on the site.
Would it be possible to have a real "cancel" button or at least that changes are taken in account only if I click on the "Accept" button?
The changes won't be processed if you don't have the preview window open. And if you choose an external browser, rather than the integrated or windowed browser, what you're describing never happens. No changes occur until you hit Make Album.
I believe there may be some rare exceptions now, but a basic tenet was jAlbum never touches the original. You should always have the original in its original state regardless of Make album, Save changes, etc.
No, I understand that. My point was for others to realize and to say regardless of what one might do in making an album, all is never lost and jAlbum will always allow you to start over with your originals intact.