<i>
For example i want to configure my article class(with image) in such way that it could only accept image file with 3:4 proportion(ex. 600 x 800 px). </i>
This is not possible by default. You can't force checking image dimensions during upload. This will require some PHP coding: new datatype or hacking existing for additional validation.
It is not exactly what you ask for, but you may scale down to a minimum width and height, then crop the image to a given proportion. That usually works for me
Hi Christian
Just a little question:
<i>scale down to a minimum width and height, then crop the image to a given proportion</i>
did U add in image.ini ex:
[ImageMagick]
Filters[]=geometry/scaleandcrop=-geometry %1x%2> -crop %3x%4+%5+%6
?? thanks