Creating a schematic figure based on an existing one
No, I think it would be insufficient to say : "Image based on [Reference]".

Because, from what you've written, it's not just the image you're using: you're also using the intellectual content that is the structure and information.

So, not only do you need to cite your reference for the image, but you also need to credit the origin of the structure and the information explicitly in its own right.

So do say:


  Image based on [Reference]


And also say something like (using the example of the image being a classification of the existing literature):


  In creating this classification, I have followed the classification scheme set out in [Reference], using information from [Reference] and [other Reference]