By default, Black Pearl Mail will upload your profile picture on your people file in the format and size that the file is originally saved in. Most images are standard square or rectangle shapes when saved, meaning most profile images are uploaded as squares when added to Black Pearl Mail.
To make your profile image show as a circle image, you will need to save the images as a circle PRIOR to uploading this into your people profile.
The below instructions outline how to achieve this.
You would need to edit the photo before loading it to the Black Pearl Mail app. The optimal image size for a user's picture is between 150X150px - 300x300px.
Here is a shortcut for re-saving an image as a rounded/circle file.
Below is a video outlining how to use this tool.
If you are using a Mac, there's another easy way to do that using tools in the Preview app. Select Markup Toolbar:
On the left side of the toolbar, click on the drop-down for Selection Tools and click Elliptical Selection.
While holding the Shift key down, click and drag a circle around your picture. You don't have to make it perfect as once you let go, you can drag the selection around and reshape it by holding down the Shift key and clicking and dragging one of the corners. Holding the Shift key while making or editing the selection will retain the circular shape.
If the image is not already in a PNG format, you will be asked to convert it to one.
You now have a profile picture in a circular format that you can load into the Black Pearl Mail app.