>>If, in each environment, you simply load and save the image without any resizing do you get identical results ?
>
>Yes, I tried that last night and that part is ok.
>
>It is in regards to the resizing process which seems to be affected by that.

Is the Windows service code using the same .NET version (esp. System.Drawing.dll). If so then I guess it's down to stepping the code to determine where the results deviate.....