I have a problem when trying to resize thumbnails (as I've just installed Showcase, it's likely due to my lack of knowledge about this addon).
Whatever can be the size I enter in "Options>Showcase thumbnail dimension", the size of the frame doesn't change but the definition of the thumbnail does :
Here is when I enter 20*20 thumbnail dimension
here is when I enter 200*200
And here is when I enter 400*400
If you compare second and third picture you'll see that picture definition is not the same. So, changing value of the field had an effect, but not the one expected.
Whatever can be the size I enter in "Options>Showcase thumbnail dimension", the size of the frame doesn't change but the definition of the thumbnail does :
Here is when I enter 20*20 thumbnail dimension

here is when I enter 200*200

And here is when I enter 400*400

If you compare second and third picture you'll see that picture definition is not the same. So, changing value of the field had an effect, but not the one expected.