Dear James,
Thank you very much for your interest on our product. Ok, actually, this control does not know who is SQL server or ORACLE or MySQL etc. This control exposes a byte[] type property (public byte[] BlobData) which can be bound to any datasource field which provide a byte[] type data. In our online documentation, we have just shown how to use with SQLDataSource Control. You can use with LINQDataSource or other datasource controls. Every Data Source handle byte[] or binary type field in it's own manner, so we need to know how to trick the data source control to match. Say for example, if you use LinqDataSource control, then, in the DBML file, you need to change the binary property of your data source from Linq.Binary to byte[] and everything will work after this change. In SQLDataSource, you dont need to do anything, simply bind the data field with the control's BlobData property and the image will be displayed. But yes, if you want to use Upload Mode (2 way data binding) then you would need to delete a single phrase in the source view of the SQLDataSource control.
Now about using in MySQL, I am not sure what would be the DataSource control you will be using but whatever datasource you would use for MySQL, there must be a easy way to bind the Blob data with your datasource.
If you need any more assistance ,you may let us know.