Custom Background Themes In Mailbird :
We are excited to announce Mailbird now lets you upload any image on your computer as a background image. To use your own background image in Mailbird:
Open the Mailbird email client.
Click on the menu and select Settings.
Select the appearance tab from the Settings menu.
In the Background section, click the first box with the “+” symbol (see image).
You will then be presented with an explorer window with which to designate the image file you would like to use as your background image..
Find the image (we recommend you do not use an image larger than 5 Mb) on your computer, select it, and click open.
That’s it! Feel free to adjust your theme color to suit your new background.