3.9Gigs is HUUUUGE. I can't say that in the last 9 years that I've ever tried to load a file that big. Unless this project is meant to be viewed from 12 inches away or is WAY oversized, I would suggest downsampling your image. A file that large is also more likely to corrupt in export from your editing software and could even possibly damage your source file. (keep yer originals safely filed away) If your source file takes a long time to load into your editing software, resample to your intended output resolution before doing anything else. Make sure all placed images are sized, cropped and then matched to your output resolution before further editing. Its easy to forget that a seemingly little image can have a super-big filesize within your larger artwork. Also, be sure to flatten/discard layers if you export to a TIFF or PDF. Hope this helps!