It's hard to find images by numbers alone, as for titles - sometimes they don't mention characters in images or are written in Japanese.
Suggestion
Option to add tag(s) to names.
User makes list of tags - bit of work is offloaded on user as it's almost impossible to predict which tags user wants added to file name.
When one of the tags matches with image tags - add that tag to file name.
Too many tags may create too long names so it would be max 2 or 3 tags added to file name.
If tag has English translation then either add both or only English.
Example
User list consists of four tags:
初音ミク
VOCALOID
ドラゴンボール Dragon Ball
ポケモン Pokémon
When downloading image with any of those tags, it's added to file name
Without English translation
111569786_p0_ポケモン
With English translation
111569786_p0_ポケモン_Pokémon
Issue
It's hard to find images by numbers alone, as for titles - sometimes they don't mention characters in images or are written in Japanese.
Suggestion
Option to add tag(s) to names. User makes list of tags - bit of work is offloaded on user as it's almost impossible to predict which tags user wants added to file name. When one of the tags matches with image tags - add that tag to file name. Too many tags may create too long names so it would be max 2 or 3 tags added to file name. If tag has English translation then either add both or only English.
Example
User list consists of four tags:
初音ミク
VOCALOID
ドラゴンボール Dragon Ball
ポケモン Pokémon
When downloading image with any of those tags, it's added to file name Without English translation 111569786_p0_ポケモン
With English translation 111569786_p0_ポケモン_Pokémon
Only English translation 111569786_p0_Pokémon