Sorry, my original post wasn't very detailed.
In the DB folder for my computer's local game files, there's four sub-folders, titled 'Database Component ID Numbered List,' 'Descriptions,' 'Images,' and 'Templates' (there's also a bunch of DB3 files, whatever those are, all named something like 'Colonial_2.3.2.db3'). The 'Descriptions' and 'Images' sub-folders both have two sub-sub-folders named 'CWDB' and 'DB3000.' Within the sub-sub-folders are the actual image and text files for the database.
In the in-game database viewer, there's a number before every entry's name. For example, the full title entry for the American AC-130J is '#3173 - AC-130J Ghostrider (United States - 2015).' That entry doesn't have a picture or a description, so it doesn't show up in either the 'Descriptions' or 'Images' sub-folders. If I wanted to add my own picture to the database viewer, I would save an image file named 'Aircraft_3173' to the appropriate 'Images' sub-sub-folder, either 'CWDB' or 'DB3000,' but I don't know which sub-database the entry belongs to. For this one I can guess that it's DB3000 since it's a pretty new aircraft, but for other entries it can be a lot harder to guess.
My question is, is there a way to tell which sub-database an entry belongs to without guessing, preferably through the in-game database viewer (i.e. not having to dig through the local files)?