You can see existing threads that answer this. This is an encoding issue, often caused by how the file was transferred to your server. If using FileZilla, use Binary mode.
Will try that! Thanks, Wulf. <3
Merged postCrap. Yeah, that didn't work. I deleted the file from the server, deleted the copy on my hard drive, set FileZilla to binary transfer, downloaded a new copy, and sent it up via http://FTP. Same error message:
(23:38:55) | Added '// Reference: Facepunch.Sqlite' in plugin 'ImageLibrary'
(23:38:55) | Added '// Reference: UnityEngine.UnityWebRequestModule' in plugin 'ImageLibrary'
(23:38:56) | Error while compiling: ImageLibrary.cs(1254,25): error CS1525: Unexpected symbol `end-of-file'