Increase Thumbnail Dimensions

The thumbnail item of the RadFileExplorer consists of an image preview icon or a folder/extension icon (txt, doc, pdf, js, etc) as shown below, e.g.:

By default, the thumbnail items of the RadFileExplorer have built-in dimension of 65x65px along with the image preview/extensionicons' size of 32x32px. The RadFileExplorer offers one additional built-in larger item size of 100x100px. Note that the built-in extension icon will be rendered as 32x32px, but the image preview thumbnail icon will be shown as 64x64px. To enable this mode set the CssClasses property to rfeLargeThumbnails:

<telerik:RadFileExplorer RenderMode="Lightweight" ID="RadFileExplorer1" runat="server" ExplorerMode="Thumbnails" CssClass="rfeLargeThumbnails">
</telerik:RadFileExplorer>

Here is the final result:

It is also possible to define custom size for Thumbnail items by overwriting the .rfeLargeThumbnails class, e.g.

/* Large thumbnails */
.rfeLargeThumbnails .rfeThumbList
{
    width: 100px !important; /*defines thumbnail wrapper dimension*/
}

.rfeLargeThumbnails .rfeThumbList .rfeFile
{
    /*the sum of the height and padding-top values should be equal to the height property defined in the rfeLargeThumbnails class*/
    width: 64px !important;
    height: 44px !important;
    padding-top: 20px !important;
}

.rfeLargeThumbnails .rfeThumbList .rfeImageFile.rfeFile
{
    height: 64px !important;
    padding-top: 0 !important;
}

.rfeLargeThumbnails .rfeThumbList .rfeFile img
{
    /*defines Image Preview Thumbnail dimension*/
    width: 64px !important;
    height: 64px !important;
}

In more specific scenarios, you can play with the above CSS using Firebug or IE development toolbar to achieve the desired thumbnail size appearance.