Prerequisites
There is no possibility to change pictures that already exist in scanned documents. You can only add new images to such files.
As this is a subscription-based feature of PDF Editor, make sure you have upgraded the app.
How to add a new image to a PDF file
Open a document.
On the top toolbar, tap Edit PDF.
Select Image .
Tap where you want to insert an image.
Choose the picture you want to add.
To edit the image, tap it and select the needed option in a pop-up menu.
You can also add images while out of the Edit mode:
Open a file.
Tap and hold on a place where you want to insert an image.
In a pop-up menu, select Image. On your iPhone, use the arrow button to access this option.
Choose an image from your device and select the image quality.
Note: To undo the changes, tap Undo on the toolbar. If you need to redo your edits, tap and hold and select Redo.
If you want to remove the pasted image, tap it and select Delete in a pop-up menu.
How to edit the image in a PDF document
Open a file.
On the top toolbar, select Edit PDF.
Tap the image you wish to edit.
Select the needed option in a pop-up menu. You can rotate, replace, crop, extract, or delete the image.
To move or resize the image, tap and hold it.
How to download an image from a PDF file
Open a PDF document.
Select Edit PDF on the top toolbar.
Tap the image you want to save.
In a pop-up menu, select Export.