Can i delete .DS_Store? ~251 MB
.DS_Store is a metadata file: it contains data about the files present in the folder. 

You can delete the file without any worries, it will only delete some settings like icon position, file previews etc. But Finder recreates the file instantly. 

Since 250MB seems to be way too much to me, even if Finder will recreate the file, it will most likely be way much lighter (&lt;1MB).