Can you attach a twbx? I will try to take a look as soon as I can.
First thing I would do is to verify if all your images have the same size (if you have multiple shapes assigned in your graph, always make sure they have the very same dimension at the beginning).
Also - look to make them full size (Size in Tableau) and see if the "Fit Entire View" is affecting (or not) the final rendering.
I will take a look to your twbx for sure!
I did some research and Custom Shapes are really for small image. But I found a workaround for you - using background image (and you can, like you need, hide this panel dynamically)!
Custom Shapes are really for small images with transparent background - background images will let you post images based on condition and give you full quality.
Here is the link to download the dashboard and explore options (background images in map option, Set, parameter)
Thank you very much for your help and the background image definitely is the solution!
Also, thank you for your brilliant idea on combining filtering and highlighting in one dashboard. I will send you the workbook with the updates through email since I couldn't attach here.
One more question I am having,
I couldn't get rid of the null size legend when there is no available data. Do you have any tip for that?
Was a pleasure, Wendy!
For the Legend - since you are hiding things, it's hard to manage.
I would go with this workaround: don't show the native Size Legend provided by Tableau and, instead, drag an image (smaller and more general) instead.
But if you go this way, you loose a level of detail
Maybe keeping the "Null" is not that bad - you can insert, in the Title of your Legend:
Null when Not Applicable
I played around with the size of picture that appears when there is no data available. It works! It covers the null legend. Please see the updated link below.
Thank you once again for your generous help!