The alt attribute is required for all images. It's value is the image description.
There is no need for any attributes in the <body> tag. Use css: Being unable to validate has a number of causes:
1. no/incorrect DTD
2. incorrect charset
3. an editor adding incompatible characters
The top of your document should look something like this:
If the document still does not validate, then remove the characters listed by the validator.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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