Use a max-width:100% in your CSS instead of width:100%.
Width: 100% upscales images which often leads to distortion.
Max-width: 100% does not upscale images beyond their native file size.
Also do not specify any height or width attributes in your HTML code.
i don't know how to do that. At the right side of my screen i see CSS all and actual and there i have filled in for everything: max-width 100 %. Is that right, because i do not see any changes?
i don't know how to do that. At the right side of my screen i see CSS all and actual and there i have filled in for everything: max-width 100 %. Is that right?
Well, your web site layout is not responsive. It's fixed width in pixels.
And Lightbox container appears to be 1020px wide. So it's not an ideal set-up for smaller device users who must scroll horizontally.
If you want responsive, look at this Bootstrap DEMO.