"You would help the developer(s) with collecting all images of the most of all android phones and make it easier for them to rename them to an logical name like: Brand_Phone_Model.png and make the background transparant in Photoshop. Resize these images to the same size of the current phone image in AirDroid and It's for the developer*s) a little job to add this function to AirDroid in my opinion
"
Why choose app to do it? As far as I know, smartphone app are complicated to use in photo resize, photo signing. So the usual thing I do is
applying watermark to photos in PC and transferring them to smartphone whenever I need them. So I don't see the hard to edit and signature issue in smartphone.