before you do anything,

the images data can be found in
"..\BlueArchive_Data\StreamingAssets\PUB\Resource\GameData\MediaResources\UIs\03_Scenario"

there will be 2 subfolders
"01_Background" and "04_ScenarioImage"

"01_Background" contains background and cutscenes images
"04_ScenarioImage" contains popup images during the story (mostly student bond story)


for this guide, we will be editing in "01_Background"

we will be editing some images here


for this case, i want the bank lobbery happen in brookhaven

we're going to find "BG_Bank"

then open up any paint tool and edit them

it'll look like this


be sure the image resolution remain the same otherwise it may look strechy (op didnt tried this)

now save and see it for yourself

you're doing great, you made me proud