Why it’s bad: It’s not scalable, meaning it will become distorted when you try to change the size to make it work on different media and online platforms. We all seen blurry and distorted images on print items and online – it looks bad and hurts credibility.
Also, not all .jpg files are printer friendly and if you need your logo professionally printed (think business cards, flyers etc.), the quality will be very poor. In fact, some printers will not work with those files at all. If you want to put your jpg logo on a background, then you will have a white box around it and it may not blend properly.
How to fix it: Have a professional designer create or re-create your logo in Illustrator so it will be in a vector format. It will now be scalable to whatever size you need. Make sure that in addition to the .ai file you also get scalable .eps and .svg files, as well as some high-definition .jpg and .png files. Designers and printers will need the .ai or .eps file when creating and printing any of your brand materials and merchandise