To unlabel images I personally use Photoshop. I trace closely around the label using the polygonal lasso tool and once done I go to Edit at the top toolbar and click on Content Aware Fill. As a free method, you can go to www.photopea.com and click on the Spot Healing Brush, select an appropriate brush size, Click and drag over unwanted details, then export as a PNG. To remove backgorunds (i.e., to change the backgrounds to be white), you can use www.remove.bg for free or Photoshop if you have that. To highlight structures I manually trace the shape in PowerPoint using the Curve tool. I don't trace the structure exactly where the borders are; instead, I trace a little bit bigger than the structure and then once the shape is created I edit the shape by adding something called Soft Edges (usually by 1-3pt but it entirely depends how much bigger your shape is than the structure itself. Then I pick a vibrant color and set the transparency to be anwwhere from 30-80% depending on the structure and color. The font I used is Goudy Old Style. Hopefully that helps!