PSP8 file saving problem

Lately,whenever I try to save a file as either JPEG,Gif or PNG(PSPImages always look fine though),there are always kinda pixel-y looking spots all over it if I close and re-open it.No matter how many times I try to remove them with either the blur tool or with Adjust/Edge Preserving Smooth,they always come back.Any idea why that happens and what I could do about it?Any help would be much appreciated.