Note: UPDF for Windows doesn't support the editing feature currently. The editing feature will be added in July.
How to Edit Images in PDF with UPDF
1. Edit Image
To edit images from your PDF document, enter the editing mode by clicking the Edit menu on the top.

Click or double-click to select the image you want to edit.
Use the revealed toolbar to rotate, crop, extract and replace the image.
Alternatively, right-click the image to reveal the tools for editing images: cut, copy, delete, rotate, replace, crop, and extract.

2. Add Image
Adding images to PDF using UPDF is pretty simple. Just click on the Edit menu on the top toolbar.
Click on the + Image icon.

After clicking the icon, you'll be asked to choose the image from your device. Click Open to insert the image to PDF.
Now, you can click the image to adjust the position and size.