When changing any images in the system make sure you rename the new image file with a different name. For example if the file name is: image.jpeg and you want to change the image to a new one MAKE SURE the FILE NAME is different - like image01.jpeg

If you are trying to save anything else and it is not saving the information, look for any special characters or apostrophes you have added in the description or any of the fields.  Apostrophes and Special Characters are not allowed in some areas - and are usually marked with warnings.