When logged into your account, go to your main profile page and from the Images / Collections / Shop menu, click on Images. Each image will show a number underneath it, this can be used to change the order of images on the page, so if you want image number 5 to be image number 10, change the edit number accordingly.
To change image order within a Collection, click 'Collection' from the Images / Collection / Shop menu, then at the top of that page, click 'Edit Collection', you will then see the options to change the order of images, select the Collection logo image etc. When completed, click the 'Submit' button to save your changes.
Thank you very much for this information. I will now have to spend significant time rearranging my pictures, but it will be worth it for pictures in a series tell a better story than everything jumbled up.