Dear all,

Suppose the original photo is 4000 x3000 pixels (about 3.6MB)?
-> is it possible to auto-resize it to say 800x600 during upload?
-> if yes, how to do?

Thanks for any kind of help!

Sorry, that's not possible.

Generally the original image uploaded is actually not changed on purpose. You might later switch the theme, need other sizes etc, so the original is always available so new sizes can be generated.

According to me, it is unsuall to upload such full sized images.
But as told by acrylian, whatever the size of your uploaded picture, zenphoto never change this original picture.

But, I desagree with fretzl : in your theme you can choice to use these full images, or sized images (eg 800px).
In that case, Zenphoto generate it on the fly and cache it.

There is a lot of zenphoto's functions to use full or sized images, to suit your need in your theme.

But fretzl is still right that there is no functionality to resize the full image on upload itself or afterwards. All sizes created are additionally.