Hi Alexandre,
I agree with you but marking those strings as translated doesn't reflect the an accurate status but the frustration is not the main reason to do that. Note that leaving those strings untranslated don't allow us to know if the module has been updated with new strings needing attention or not, so if I leave a module at 99% with some image strings not translated I will revisit that module to check if that 99% is due to new translatable strings or due to the untranslated images.
So I'm sorry for disagreeing but in muy case I will keep translating those strings to avoid wasting time re-checking modules again and again until we can reach a better solution for that.