Allow resizing of images in properties and tables

Images in regular rem can be easily resized by dragging the corner. However, as I convert more of my RemNote structure to tables, I find that I lose the ability to resize when I copy the image to a property.

This is mostly motivated by the desire to have useful and pleasing image sizes in my knowledgebase, but also to be able to better control how images look in tables (though the control of images sizes in tables may merit an additional feature request).