Hey Mona, thanks for getting back to me. I have taken some screenshots of what I am trying to do so you can see exactly what is not working.
I open up the PowerApp on my android device and fill out the form as shown below. You can see two attachments. One is a jpg and the other is a pdf. I then click on the submit check mark in the upper right hand corner.
I then go over to the SharePoint list and find the item on the list.

When I click on that list item only the PDF file is shown as an attachment.

The jpg file I attached was only 4.26 MB. The PDF file was 2.56 MB. The attachment control in the PowerApp is set to have 6 attachments as the maximum and the attachment size cannot exceed 10 MB. I would try other types of image files, but since jpg is what most people would have, that file type really needs to work.