I was allready successfull to resize pictures to place them with the right relations in a picturebox (I have to present 16 pictures - just like thumbnails - on a form; the original imagesizes can go up to 6 MB).
Problem: it takes too much time.

My procedure:
Load picture in SpecialPicturebox
Estimate the Height and Width
If Height>Width then Calculate scalingfactor1 else Calculate scalingfactor2
load picture in Picturebox1 with proper scalingfactor

(Imagebox with autostreching gives deformed pictures!)

Previewing 16 pictures in my solution can take 10 sec, previewing them in Windows explorer will take only 0,1 sec (estimate).
Who has a faster solution?