You can create a plugin, create a new product image widget that can make use of zoom functions. Then when you install plugin, the widget will be listed in available plugins. You can then remove default widget and use your zoom widget instead.

Ray, thanks for the heads up!

Mazhar, that works great for displaying custom info. But what would the process look like for updating the Admin to create the zoom image when uploaded? Currently, the AssetsController creates 3 versions of specified dimensions. We would like it to create a 4th larger version. Do we customize the AssetsController and associated views directly, or is there a way to override/replace it with a plugin that doesn't require touching the original code?

Note that this is just one example. We are going to want custom product fields displayed right on the Add/Edit product page, add address validation, fraud processing, etc. Going to be a ton of work which is why I want to make sure we are doing things in a manner that will allow for easier upgrades.

I might try writing an ImageUpload plug-in that essentially copies what you have in the ImageUpload portion AssetsController, but adds a 4th image, and uses an exact route in the RouteProvider.

I was able to create a plugin that took over the AssetController ImageUpload action and views. My Config page had settings for zoom width and height that were stored in the CustomFields table. I essentially copied the logic, added my customizations to create the zoom (which included looking at the EXIF data b/c AC was rotating some images).

However, after doing so I realized what a pain it is going to be to maintain when AC releases updates. Since AAC updates don't touch my plugins, I have to know everything AC changes with an update to make sure I update my plugins accordingly. If I just do it in the AC source, I can use source control and WinMerge to merge changes and keep things running smoothly.