YouTip

## ASP.NET Web Control: Image.ImageUrl Property The `ImageUrl` property is a core property of the ASP.NET `Image` Web Server Control. It is used to get or set the URL (path) of the image to be displayed on the web page. --- ## Definition and Usage The `ImageUrl` property specifies the location of the image file that the `Image` control will render. This path can be: * **Relative to the current page** (e.g., `images/logo.png`) * **Application-relative** using the tilde (`~`) operator (e.g., `~/images/logo.png`), which resolves to the root of the web application. * **Absolute** (e.g., `https://www.example.com/images/logo.png`) --- ## Syntax ### Declarative Syntax ```xml ``` ### Property Values | Value | Description | | :--- | :--- | | `URL` | A string representing the path to the image file. | --- ## Code Examples ### Example 1: Basic Declarative Usage The following example demonstrates how to set the `ImageUrl` property statically in the `.aspx` markup. ```xml

``` ### Example 2: Dynamic Usage in Code-Behind (C#) You can also set or change the `ImageUrl` dynamically at runtime using server-side code. **ASPX Markup:** ```xml

``` **Code-Behind (C#):** ```csharp protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { // Set the image URL dynamically using an application-relative path DynamicImage.ImageUrl = "~/images/banner_summer.jpg"; } } ``` --- ## Key Considerations 1. **Application-Relative Paths (`~`)**: When working with nested directories, it is highly recommended to use the `~` operator (e.g., `~/images/pic.jpg`). ASP.NET automatically resolves this to the application root, preventing broken image links when pages are moved to different subfolders. 2. **Alternate Text**: Always pair the `ImageUrl` property with the `AlternateText` property. If the image specified in `ImageUrl` fails to load, or if the user is using a screen reader, the `AlternateText` will be displayed/read instead. 3. **Supported Formats**: The `ImageUrl` can point to any standard web-compatible image format supported by modern browsers, such as `.png`, `.jpg`, `.jpeg`, `.gif`, `.svg`, or `.webp`.