Are your email signature images changing size or showing much larger when you install the signature in your email client?
The most common reason for email signature images changing in size is because the image resolution (in DPI) is not set to 96 DPI for Outlook, or 72 DPI for Apple Mail.
If your DPI settings are too high, you’ll likely end up with an enlarged image in your email signature. This happens because Microsoft Outlook and Apple Mail scale images using the DPI value.
To fix this, you will need to use an image processing tool such as Photoshop to change the DPI setting on the image.
Lets take a look at what DPI is and how you can fix this issue.