There is some legacy code I need to change from <asp:ImageButton to an html <img tag. All the following tags are staying the same. My problem is that the back end is not picking this up. I've removed any instance where there was logic on the type ImageButton but i'm still getting a run time error:

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https://i.redd.it/fiurx7o0zxh21.png

A quick peak at the designer file and it has picked up the change, so if there are no references to the type WebControls.ImageButton in the .cs file, and the designer file looks to have acknowledged the change, where else should I be looking to correct this error?