I don’t think it would really justify it to be detected as malware. A joke, maybe…

It doesn’t contain the whole images, but in particular for the BAT files, it’s necessary to look at the “bigger picture”, probably the whole file.
Detecting the single lines would produce too many false positives.

Generally, detecting tiny BAT files is quite hard if you don’t want to have false positives - because it’s hard to decide whether it’s always malicious, or if somebody can use it for ordinary tasks (such as formatting disks, cleaning unused drives, …)