Changing thumbnail size in Image Gallery

Changing thumbnail size in Image Gallery

February 11, 2013 0 Comments

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As with most of our blog posts this one is also a result of constructive client feedback, submitted through the support channel.

The following post will briefly demonstrate the ability to modify the default thumbnail size in Image gallery frontend widget, without affecting the image quality.

 By default the logic that concerns thumbnail generation is implemented in the ConfigureDetailLink() method of Telerik.Sitefinity.Modules.Libraries.Web.UI.BaseMasterThumbnailView<T>. As you have probably guessed already, inheritors of this class are the MasterThumbnailView classes used in Images, Videos and Documents for displaying the thumbnails mode of the respective ContentView controls.

This makes our task very easy, as we can inherit from the desired MasterThumbnailView, and override the ConfigureDetailLink, where we can pass a custom thumbnail size.

In our case we'll be modifying the Image Gallery's thumbnail view, so our class of interest is Telerik.Sitefinity.Modules.Libraries.Web.UI.Images.MasterThumbnailView, so we can say:

using System;
using System.Linq;
using Telerik.Sitefinity.Modules.Libraries;
using Telerik.Sitefinity.Modules.Libraries.Web.UI.Images;
namespace SitefinityWebApp
    public class MTVCustom : MasterThumbnailView
        protected override void ConfigureDetailLink(System.Web.UI.WebControls.HyperLink singleItemLink, Telerik.Sitefinity.Libraries.Model.Image dataItem, Telerik.Web.UI.RadListViewItem item)
            int tmbSize = 400;
            singleItemLink.ImageUrl = dataItem.ResolveThumbnailUrl(size: tmbSize);
            singleItemLink.Text = dataItem.AlternativeText;
            singleItemLink.ToolTip = dataItem.Description;

and then configure Sitefinity to use this view in Administration->Settings->Advanced->ContentView->Controls->Images Frontend->Views->ImagesFrontendThumbnailsListBasic->ViewType where you can type the CLR type of your new view.

Please keep in mind that the default CSS applied to the thumbnails corresponds to the 120px size, so you might need to adjust it additionally, for example:

.sfimagesTmbList .sfimagesTmb {
  width: 200px;
  height: 200px;
.sfimagesTmbList a {
   width: 200px;
  height: 200px;

For your convenience please find attached the above sample here, and feel free to modify it as per your desired use case scenario.


The Progress Team

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