This question has been answered by jgrant. See the first response.
Then the rotation works but it doesn't get along with the ric filter.
<img class="img-front" src="[[phpthumbof? &input=`[[+tv.img_frontTV]]` &options=`w=263&h=436&f=png&fltr[]=ric|110|200&fltr[]=rot|15|006699` &debug=`1` ]]" alt="dot1" width="263" height="436" />
I hadn't thought about the php versionor MODX or phpThumbOf getting in the middle, as I saw this working in Belafonte's Blog(http://www.belafontecode.com/image-manipulation-with-phpthumbof-in-modx-revolution/) with modx Revo so I guess php v5.2+...
phpThumb is rather old; it could be that it works properly with PHP 4.X or such, but not 5.4. Also, have you tried taking the whitespace out and running all the options together? (`w=263&h=436&f=png&fltr[]=ric|110|200&fltr[]=rot|15|006699`) That probably won't help any, but it's easy to try...
Those pictures come from the end user who uploads 3 different images together with an article. Then, after resizing them, they're used in a slider who needs the images with a specific size. You know you can't ask the user to resize the image just as it's needed, with the proper aspect ratio. That's what I prefer about this preprocess, it works no matter the size of the picture uploaded by the user, and if he just uploads his 3MB picture from his camera, you don't have to download such a monster...
You could also get the same effect with CSS, which is what I'd do.
Those pictures come from the end user who uploads 3 different images together with an article. Then, after resizing them, they're used in a slider who needs the images with a specific size. You know you can't ask the user to resize the image just as it's needed, with the proper aspect ratio.
With phpThumbOf, with the option &f=png, the cache filename was alwas the same, no matter of the extension of the input file. With pThumb, this was corrected.
firefox understands transform (as does Opera) and doesn't need any vendor prefix (so -moz-transform:rotate() doesn't exist -you use just the standard expression transform:rotate)