Upload image via iPhone is not working.

Hi ,,
Almost all of my clients who are using iPhone are unable to proceed to complete their order because of the following described issue:
– When an image had uploaded to a (Required) field via iPhone the upload completed normally but when the client had pressed (Place order) button a message showed (file is a required field), although the max upload size is (102000 KB) and the file seems to be uploaded right, but when the client edit the photo and crop it the uploaded file accepted normally and he can proceed to place the order.