Online image resizer

[sk8ar]

I have created an online image resizer and I would like to know what kind of resizing would fit the best to customer (someone who wants to resize image).

By percentage
max width
max height
fixed dimension (manual chosen)
something else...

On my website(online image resizer) I am currently using by percentage but what type of resizing would fit you the most ?

 

[lee101]

Export format could be useful, and if applicable Jpeg compression.

 

[jido]

I think a good compromise is width-based depending on the image ratio. Specify a target width, and 3:2 or 4:3 images are resized this exact width. Wider images are resized a bit more than the target, narrower (or vertical) images are resized less than the target. I actually have a formula if you are interested.