I feel for you man, that must be quite a long and tedious process.
I don't know if you also need to save the translation because you want to make your Russian version, but if I may I'd suggest the app Google Translate (Android/iOS) that works in Augmented Reality now and it will superpose the translation to the text you are point your phone to. Here's an example (I've no idea about the quality of the translation though...)
View attachment 1232097
(note that there it was paused to allow me to take the screenshot but it actually works in realtime)
You can use this if you just want to enjoy a little bit more the game instead of keep saving the images.
And if you need to translate the dialogues, I think it's better to work directly in the .rpy so that the copy/paste can ease the task.
Sorry if these advices are not helpful because for some reasons they do not fit with your needs, but you really triggered my congenital laziness for repetitive tasks !