Thomas- First let me apologize for suggesting that PhotoImpact will open a *.sid file. It will not, at least with file extensions sid, jpg and bmp.
I did have a few map file downloads saved from a dying hard drive, but it turns out that all but one were in formats other than sid. The Mr. Sid Setup file had survived the crash, so i installed it again. It works.
So, yes, there may be a need for Mr. Sid support. Point well taken. John