Upgrade From 1.4 To 1.6 Image Url To Be Like 1.4. External Image Link Not Working

[energypb]

I am starting the upgrade my shop from 1.4 to 1.6, I have been able to get the image to work after a lot of reading around for the upgrade. The issue that i am having is that on my 1.4 install the image URL to the 1.6 are not the same and I need to get them to be the same as many of our customers have linked the images to our products on there blocks. Once i test the upgrade all the old links go to "?" image. 

 

The URL format in 1.4 is 

 

url.com/1234-5555-large/productname.jpg

 

1.6 is 

 

url.com/1234-large_default/productname.jpg

 

So it seems that 1.4 url it is product ID + some number how can i get the some number back ? Or can i do something in the function that the pages on 1.6 work with the new format and some type of function or rewrite will still resolve the other number URLs ?

 

Thanks for your help. This has become a blocker for me on my upgrade path. I am very excited to upgrade as 1.6 is a new wold from 1.4.