Here is what to do if you want to have a background image that will automatically re-size itself according to the browser windows size (thus also for different screen resolutions).
First off be sure to get a nice large image around 16:9 ratio size having preferably 1900 px width, reduce its size (not in pixels, as in kbs) so it is not larger than 300-450 kbs(even this is too large but it will do).
Then upload it to someplace where you can have a direct link to it.
Finally go into "Edit HTML" from the design tab. Find "body {" in the css section. (just searching that quote without the quotes will get you there if you can't see it). It will most likely look something like this:
body {
font: $(body.font);
color: $(body.text.color);
background: $(body.background);
}
Now, replace this part;
background: $(body.background);
with this;
background: url(http://www.yoururl.com/your_image.jpg) no-repeat center center fixed;
-webkit-background-size: cover;
-moz-background-size: cover;
-o-background-size: cover;
background-size: cover;
You should have something like this as the final result;
body {
font: $(body.font);
color: $(body.text.color);
background: url(http://www.yoururl.com/your_image.jpg) no-repeat center center fixed;
-webkit-background-size: cover;
-moz-background-size: cover;
-o-background-size: cover;
background-size: cover;
}
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font: $(body.font);
color: $(body.text.color);
background: $(body.background);
}
Now, replace this part;
background: $(body.background);
with this;
background: url(http://www.yoururl.com/your_image.jpg) no-repeat center center fixed;
-webkit-background-size: cover;
-moz-background-size: cover;
-o-background-size: cover;
background-size: cover;
You should have something like this as the final result;
body {
font: $(body.font);
color: $(body.text.color);
background: url(http://www.yoururl.com/your_image.jpg) no-repeat center center fixed;
-webkit-background-size: cover;
-moz-background-size: cover;
-o-background-size: cover;
background-size: cover;
}
This will work in most of the latest versions of known browsers.
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