You need to use the correct format. There are times when a JPG image is required and there are times when a GIF image is better. Generally speaking GIF images are better for logos while JPG images are better for photos.
2. Size / Resizing
Before you insert an image in a web site, the size of the image has to be exactly what you need it to be on the site. In a Word doc you can insert a huge image and simply resize it right there in Word, but you can't do the same in your HTML editor. Yes, HTML editors allow you to do that, but it's the wrong way to do it. If you need it in a specific size and you don't know how, please let us know. We will resize it the correct way and send over the new file. No charge.
By the way:
The correct way is to open the image in PhotoShop (or similar) and resize it using the resample tool.
We supply transparent background images which allow you to place your logo on any background. Only some formats support transparency though. JPG, for example, does not. Among the logo files we sent will be two files called "logo.png" and "logo-transparent.psd". Both of these are high-resolution files with transparent backgrounds. Either will work perfectly. Some resizing will be required though if you are using them for the Web. Let us know if you have trouble resizing the logo.
If you just can't get your logo to look right on your site, we offer a web integration service. It's pretty inexpensive. Most of the time you'll pay only $50 to $100 to have a Biz-Logo pro take care of it for you. Please send us an email with your logo name and web site address. We'll take a look and let you know the cost.