upload image : how to fix the dimension height and width ?

[eluser]Matalina[/eluser]
depending on what size is more impotant to you you can set the width that must be reached the other will be larger or smaller depending on the size of the other dimension.

master_dim auto auto, width, height Specifies what to use as the master axis when resizing or creating thumbs. For example, let's say you want to resize an image to 100 X 75 pixels. If the source image size does not allow perfect resizing to those dimensions, this setting determines which axis should be used as the hard value. "auto" sets the axis automatically based on whether the image is taller then wider, or vice versa.