Comment 3 for bug 685893

it is not possible to "just make a warning". when this error happens it is because the algorithm can't solve the problem.

that said, there could be a better way than frustrating the user with an error message and no result after hours of crunching.

to my understanding, enblend adds one image at the time. how about adding a switch to keep the previous results?

example:

images: [1,2,3,4,5]

blend 1 and 2 => success. save 1+2 as temp result.
blend 1+2 and 3 => success. save 1+2+3 as temp result and discard 1+2.
blend 1+2+3 and 4 => error. fail, but leave 1+2+3 on the user HDD.

this leave the user with the option of either blend 1+2+3 and 5 or (as today), remove image 4 from the set and start from scratch with bending [1,2,3,5]