A common issue that email users encounter when creating an email signature is to find it went through completely blurry or pixelated after hitting Send.
For those of you more familiar with digital image formats, the issue itself is fairly straightforward: the image needs to be created at a 96dpi, or else Outlook will reconvert it to match that setting.
I’ll be Blurry!
But for readers who don’t know what this means: when image files are generated, say a JPEG file, one piece of information that is hardcoded is the Dots-Per-Inch ratio (DPI) at which the image should be printed.
Yup, that’s how it goes, it’s a parameter meant for print, and that does not make sense to be used in a digital context; but it is. Many (if not most) applications ignore this information to display your image (as they should) and display it using the provided width and height attributes, but others, such as Outlook, do take it under consideration.
So Outlook will read your file and if its resolution is set to anything but 96dpi it will immediately convert it before sending the e-mail. The conversion process results in visible loss of quality, partly because that happens every time you process a lossy file format (as a JPEG) but also because Outlook does this with in a very generic and unoptimised fashion.
There are no builtin ways in Windows to save an image with a specified DPI setting, but there are plenty of free tools that help you this:
Paint.NET – download
Image > Resize > (Pixel Size) Resolution:
Set the dropdown to “pixels/inch” and type in 96,00
IrfanView – download
Open an image, click the “i” icon on the toolbar, change the DPI and save the image.
On software such as Photoshop, you can set this parameter in many ways, but most the simplest way it to do it when exporting for Web.