Image Size is a Chrome add-on developed by itcharliexu. It is a useful tool for checking the size of images on webpages. The add-on compares the style size and the actual resource size of each image on the page and provides a reminder if they are not consistent.

With Image Size, you can quickly view the dimensions and file sizes of images on preview pages. It also offers a copy CSS function for easy styling. For non-preview pages, the add-on traverses the entire webpage to compare the image style sizes with their actual resource sizes. It then marks any inconsistencies for easy identification.

Once installed, you can toggle the add-on on or off by clicking the icon. Right-clicking the icon allows you to access the options for the add-on. Here, you can customize the tag colors, adjust the visual width, set the maximum compatible width, specify the navigation height, choose whether to include background images in the check, and enable debug mode.

For pages with image previews, the basic information of each image is displayed in the top left corner. On non-preview pages, any images with errors are marked on the right side of the page. Clicking the tag reveals the error details, including the image preview, location, link, style size, actual size, type (image or background), and the specific DOM object on the page.