Replacement for the sitefinity image asset field control, allows you to set a microdata attribute as well (among other things)

SimpleImage

using System;
using System.Linq;
using System.Web;
using Telerik.Sitefinity.Configuration;
using Telerik.Sitefinity.DynamicModules.Model;
using System.Web.UI;
using Telerik.Sitefinity.Model;
using Telerik.Sitefinity.Model.ContentLinks;
using Telerik.Sitefinity.Modules.Libraries;
using Telerik.Sitefinity.SitefinityExceptions;
using Telerik.Sitefinity.Web.UI.ContentUI;
using Telerik.Sitefinity;
using Telerik.Web.UI;
using System.Web.UI.WebControls;
using SitefinityWebApp.Code.Configuration;

namespace SitefinityWebApp.Usercontrols.Widgets {
    /// <summary>
    /// Sample:
    /// <gs:SimpleImage runat="server" ImageDataField='<%# Eval("MainImage") %>' IsThumbnail="True" ShowTitle="True" IsLink="True" Type="dictionary" Title='<%# Eval("Title") %>' UrlName='<%# Eval("UrlName") %>' />
    /// </summary>
  public class SimpleImage : System.Web.UI.UserControl {
        protected void Page_PreRender(object sender, EventArgs e) {
            LibrariesManager manager = LibrariesManager.GetManager();
            LiteralControl imageLiteral = new LiteralControl();

            var imageLink = this.ImageDataField;
            if (imageLink != null)
            {
                if (imageLink.Count() > 0)
                {
                    var link = imageLink.First();
                    if (link != null)
                    {
                        try {
                            var image = manager.GetImage(link.ChildItemId);
                            SetupImage(image, imageLiteral);
                        }
                        catch (ItemNotFoundException iex) {
                            this.AssignDefault(imageLiteral);        
                        }

                    }
                }
                else {
                    //Get the default image from the config
                    this.AssignDefault(imageLiteral);
                }

                //Add wrapper
                imageLiteral.Text = "<div class='simple-image-wrapper'>" + imageLiteral.Text + "</div>";

                this.Controls.Add(imageLiteral);
            }

            if(this.ImageModel != null){
                try
                {
                    SetupImage(this.ImageModel, imageLiteral);
                }
                catch (ItemNotFoundException iex)
                {
                    this.AssignDefault(imageLiteral);
                }
            }
        }
  
        private void SetupImage(Telerik.Sitefinity.Libraries.Model.Image image, LiteralControl imageLiteral) {
            var imageUrl = image.Url;

            if (this.IsThumbnail) {
                var thumb = image.Thumbnails.FirstOrDefault(x => x.Name == this.ThumbnailName);

                if (thumb == null) {
                    imageUrl = image.ThumbnailUrl;
                }
                else {
                    imageUrl = thumb.ResolveMediaUrl();
                }
            }

            if (this.RequiredHeight != -1) {
                if (image.Height < this.RequiredHeight) {
                    imageUrl = imageUrl + ((imageUrl.Contains("?")) ? "&size=" + this.RequiredHeight : "?size=" + this.RequiredHeight);
                }
            }

            if (this.IsLink) {
                var detailUrl = String.Empty;

                switch (this.Type) {
                    case "Dictionary":
                        detailUrl = String.Format("/ingredients/{0}/{1}", this.UrlName[0].ToString(), this.UrlName);
                        break;
                    default:
                        //Simple Link
                        detailUrl = string.Format("/{0}/{1}", this.Type.ToLower(), this.UrlName);
                        break;
                }

                imageLiteral.Text = String.Format(@"<a href='{2}'>
                                                              <img src='{0}' {1} {4} {5} {6} />
                                                              {3}
                                                          </a>",
                    imageUrl,
                    (!String.IsNullOrEmpty(image.AlternativeText)) ? "alt='" + image.AlternativeText + "'" : "",
                    detailUrl,
                    (this.ShowTitle) ? "<span class='title'>" + this.Title + "</span>" : "",
                    (!String.IsNullOrEmpty(this.ItemProp)) ? "itemprop='" + this.ItemProp + "'" : "",
                    (this.Width.HasValue) ? " width='" + this.Width.Value + "px'" : "",
                    (!String.IsNullOrEmpty(this.CssClass)) ? "class='" + this.CssClass + "'" : "");
            }
            else if (this.AsBackgroundImage) {
                imageLiteral.Text = String.Format("<div style='background: url(\"{0}\") no-repeat center center; background-size: cover' {1}></div>",
                    imageUrl,
                    (!String.IsNullOrEmpty(this.CssClass)) ? "class='" + this.CssClass + "'" : "");
            }
            else {
                imageLiteral.Text = String.Format(@"<img src='{0}' {1} {3} {4} />
                                                              {2}",
                    imageUrl,
                    (!String.IsNullOrEmpty(image.AlternativeText)) ? "alt='" + image.AlternativeText + "'" : "",
                    (this.ShowTitle) ? "<span class='title'>" + this.Title + "</span>" : "",
                    (!String.IsNullOrEmpty(this.ItemProp)) ? "itemprop='" + this.ItemProp + "'" : "",
                    (!String.IsNullOrEmpty(this.CssClass)) ? "class='" + this.CssClass + "'" : ""
					);
            }

            if (this.ShowCredit)
                this.AssignCredit(imageLiteral, image);
        }
  
        private void AssignDefault(LiteralControl imageLiteral) {
            //Get the default image from the config
            if (!String.IsNullOrEmpty(this.DefaultImageKey)) {
                var defaultImageKey = Config.Get<GourmetSleuthConfig>().DefaultImages[this.DefaultImageKey];
                if (defaultImageKey != null) {
                    LibrariesManager manager = LibrariesManager.GetManager();
                    var image = manager.GetImages().FirstOrDefault(x => x.ItemDefaultUrl == defaultImageKey.ImageUrl);


                    if (image != null) {
                        string imageUrl = (this.IsThumbnail) ? image.ThumbnailUrl : image.Url;

                        imageLiteral.Text = String.Format(@"<img src='{0}' {1} {3} {4} /> {2}",
                            imageUrl,
                            (!String.IsNullOrEmpty(image.AlternativeText)) ? "alt='" + image.AlternativeText + "'" : "",
                            (this.ShowTitle) ? "<span class='title'>" + this.Title + "</span>" : "",
                            (!String.IsNullOrEmpty(this.ItemProp)) ? "itemprop='" + this.ItemProp + "'" : "",
                            (!String.IsNullOrEmpty(this.CssClass)) ? "class='" + this.CssClass + "'" : "");
                    }
                }
            }
        }

        private void AssignCredit(LiteralControl imageLiteral, Telerik.Sitefinity.Libraries.Model.Image image){
            bool hasText = false;
            string creditText = String.Empty;
            var creditName = image.GetValue<string>("CreditName");
            var creditUrl = image.GetValue<string>("CreditUrl");

            //Has name and link
            if(!String.IsNullOrEmpty(creditName) && !String.IsNullOrEmpty(creditUrl)){
                creditText = String.Format("<div class='image-credit'><a href='{0}'>{2} {1}</a></div>", creditUrl, creditName, this.PhotoCreditText);
                hasText = true;
            }else{
                //Has name OR link    
                if(!String.IsNullOrEmpty(creditName))
                    creditText = String.Format("<div class='image-credit'>{1} {0}</div>", creditName, this.PhotoCreditText);
                else if(!String.IsNullOrEmpty(creditUrl))
                    creditText = String.Format("<div class='image-credit'>{1} <a href='{0}'>{0}</a></div>", creditUrl, this.PhotoCreditText);

                hasText = true;
            }

            if (hasText)
                imageLiteral.Text += creditText;
        }

        public string DataFieldName { get; set; }
        public string DefaultImageKey { get; set; }

        private bool _isThumb = true;
        public bool IsThumbnail
        {
            get { return _isThumb; }
            set { _isThumb = value; }
        }

        private string _thumbName = "medium";
        public string ThumbnailName {
            get { return _thumbName; }
            set { _thumbName = value; }
        }

        private bool _showTitle = false;
        public bool ShowTitle
        {
            get { return _showTitle; }
            set { _showTitle = value; }
        }

        private bool _isLink = false;
        public bool IsLink
        {
            get { return _isLink; }
            set { _isLink = value; }
        }

        private bool _showCredit = false;
        public bool ShowCredit {
            get { return _showCredit; }
            set { _showCredit = value; }
        }

        private int _requiredHeight = -1;
        public int RequiredHeight {
            get { return _requiredHeight; }
            set { _requiredHeight = value; }
        }

        private int _maxheight = -1;
        public int MaxHeight {
            get { return _maxheight; }
            set { _maxheight = value; }
        }

        private bool _asBackgroundImage = false;
        public bool AsBackgroundImage {
            get { return _asBackgroundImage; }
            set { _asBackgroundImage = value; }
        }
        
        public string ItemProp { get; set; }

        public ContentLink[] ImageDataField { get; set; }

        public Telerik.Sitefinity.Libraries.Model.Image ImageModel { get; set; }

        private string _type = String.Empty;
        public string Type
        {
            get
            {
                if (_type == String.Empty)
                    _type = HttpContext.Current.Request.Url.Segments[1].ToLower();
                return _type;
            }
            set{
                _type = value;
            }
        }

        public string Title { get; set; }
        public string UrlName { get; set; }
        public int? Width { get; set; }
        public int? Height { get; set; }
        public string CssClass { get; set; }

		private string _photoText = "photo credit:";
		public string PhotoCreditText {
			get { return _photoText; }
			set { _photoText = value; }
		}
	}
}