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The Theme Manager is used to control the look and style of your e107 website. The 0.7 install provides 13 standard themes to choose from. More can be installed, including those you have made yourself.
Configure Current Themes
Your e107 website uses two themes, one for the public website, and a second for the Admin Area. When you installed e107 0.7, they default to Reline for the Site Theme and Jayya for the Admin Theme. In most cases, there are theme options to control the layout of your website.
Each theme can have multiple stylesheets. For Example:
Reline has two options:
Jayya has 3 Style options.
Preload Theme Images
Preloading the theme images can speed up your website (all images are already loaded in the cache of your browser), or slowing it down (if there are a lot of graphics it might slow down the initial page load). Play around with it and see what setting suits your individual site the best. 
Jayya has 6 Layout Styles to choose from. These change the way the main icons are displayed. Play around with them to find your favourite.
You can upload valid theme zip files directly in the Theme Manager, depending on your upload Preferences. Browse to select the file and click Upload Theme. Alternatively, upload unzipped files using FTP to the e107_themes directory.
NOTE: 'Third Party Themes' are not developed or tested by the e107 core developer or support teams, as such they are not guaranteed to work or worse may break your site. Test any downloaded themes before you apply to a production system. Third Party Themes are available from themes.e107.org.
You can build your own Theme. A good start would be to take a copy of one of the standard themes and save it with a new name. This will save it from being overwritten in upgrades and save you work! See.
This area displays a list of themes with screenshots and a description of the themes installed in your e107_themes directory. There are three options to choose from
Remember to check the options.