This simple application takes a character sheet and inserts an image into it. It fixes some issues where the exported PDF from D&D Beyond (for instance) lacks a character portrait. It knows about a few of the standard character sheet formats. Otherwise, use the manual selection mode to draw a box with your mouse to select the area where the image should be placed.
Note: Form-fillable PDFs may not work as expected, as the image may appear under a fillable form field. Consider flattening the PDF first (for instance, using the "Print to PDF" option in your browser) to ensure the image is added correctly.