Crosspixel is a free Chrome add-on developed by aishek that allows users to place images above webpages to create pixel-perfect HTML markup. With this add-on, users can easily overlay an image onto a webpage for design purposes.

To use Crosspixel, simply click on the extension's icon. If a file named "design.png" exists, it will be automatically placed over the page. If there is no "design.png" file, users can simply drag and drop an image onto the page, and it will be placed over the webpage.

Crosspixel also provides options to change the opacity of the image using left and right clicks. To remove an image placed over a page, users can simply click on the extension's icon again.

The image is centered horizontally on a blue translucent background. The width of the superimposed image in pixels is displayed in the Developer Tools console. It is convenient to change the width of the window with Developer Tools enabled, as the size of the window in pixels is shown in the upper right corner.

Crosspixel is a useful tool for web developers and designers who need to create pixel-perfect HTML markup by overlaying images onto webpages. Its simple interface and easy-to-use features make it a valuable add-on for Chrome users.