I have problems with uploading images to my internet printing company when the images have been manipulated through CS6 and i have saved images as jpeg the printer company tell me they are not j peg,
but images saved from my phone or camera images that have not been manipulated upload fine, What am i doing wrong?
Save/Export them as JPG. Photoshop defaults to PSD, so make sure you select JPG and not just rename the file to .jpg.
There are two ways to save them as JPG: Regular Save as option or Save for Web & Devices
Take your pick.
File > Save for Web. Select JPEG. Optimized. Best quality setting 100%.