Email signature blurry for Gmail

[sabrinar1918635]

I have created an email signature dimensions 750px by 250px. I have tried saving it as PNG and JPG files in 300dpi (this is too large when placed into Gmail) 150dpi (size doesnt change but image becomes pixelated) and 72dpi (blurry but right size). Is there a way I can make this png crisp? 

I have turned my text to oulines and image has no mask on it. 

[sishamIAGD]

When viewed on here it doesn't look pixelated if i'm honest..? Well no more than you would expect from a .png or .jpg

[Monika Gause]

There aren't enough pixels in it to be super crisp. You are probably viewing this on a HiDPI device. 

It's not a good idea to have this kind of email footer anyway. Images are turned off in many email readers automatically and then people don't see your information.