Win7. And Photos

I have Win7. and it is 64 Bit.

I put all my Photos in a Folder and if I want to Print one I do this.

I Click on one.
Then I pick Print.
Then I put my Printer in the Dropdown Box.
Then I select my Photo Size 6x4 Inch.

And Click Print and all works.

So now I cut all these Papers the size of 7x3 Inch.

Because I made a Coupon and Exported it as a JPEG.

The size of it is 7x3 Inch.
So I put this into my Folder with my Photos and I select it.
Then Click Print.
I go to pick the size from the list.

But I do not see 7x3 Inch I see 5x6 Inch.

But I do see Costum.
So I click it but I still see no 7x3 Inch.

And it does Print on the Coupon Papers I made but it is all out of the scene.

How can I get it to Print on the 7x3 Coupon Paper and look Right?

 

MG 7520 Pixma.

I just found out my Printer can not do Costum Size Printing.
Thanks.