98 SE - Two problems

#1

In Windows Explorer, righthand panel in Web mode and containing various types of pictures.

Selecting a .BMP file produces a thumbnail on the left sideof the panel - That's fine !

It used to do it for .JPG files &c, but doesn't now.

What has the machine (or I ) done ?

More importantly, what must I do or re-do to get all my pictures thumbnailing again ?

#2

Internet Explorer 6 works fine, but pictures included in a webpage are generally 'behind jail bars' !

That is to say they have a random number of vertical , generally reddish, evenly spaced lines on them.

If copied to a file , they reproduce perfectly and without the bars.

How do I stop the bars appearing on the webpage ?

Your comments gratefully received.

Phil26