Symphony.

A new extension, “Advanced Upload Field” is now available for download. Comments and feedback can be left here but if you discover any issues, please post it on the issue tracker.

Anyone using this extension can tell me how do I work with resize and all the other functions of the built-in PHPThumb library?

The only thing the extension does is calling the resize-function of the included PHPThumb library before saving the file to disk. You can only set the maximum dimension parameters of this function in the configuration of the field.

So if I set 1024x768 as maximum sizes when I try to upload a image of 1280x1024 it will automatically resize it for me as 1024x768?

It will scale the original image proportionally to fit in the maximum dimensions. so the generated image might be smaller than the maximum dimensions, depending on the ratios.