The images you choose to test will depend on where you are in the design process. If you are testing a current website, then upload screenshots of your website. If you are just getting started, then upload screenshots of your early designs, or a clearly-drawn wireframe.

You can upload JPEG (.jpg) or PNG image files of any size or dimension. Images that are high-density (retina) will be automatically scaled down to fit a regular screen. You can control how images should be displayed to participants with different screen sizes using the 'Image Options' settings described in more detail below.

We recommend you preview your study on different screens after you've uploaded your images to make sure they are not too big for the screen you expect participants to use. For example, if you are asking participants to complete the activity on a mobile device, preview your study on a mobile device.

You can see a demo study that tests a wireframe here.

You can add images by clicking the 'Choose image' button to the right of the task text box. An image uploader pop up will appear, and you can either drop image files into it or browse for your desired image file.

Once the file has uploaded you should edit your image title so that you can identify it easily in your results.

When uploading an image to first-click testing, it's important to keep in mind the PPI (pixels per inch) of the image file. This is because we calculate a scaling percentage for an image, based on the width, height and PPI of the image.

I.e. an image with dimensions 1200x800px and 150ppi will set the max-width to 576px. Whereas an image with 1200x800px and 72ppi will set the max-width to 1200px.

This auto-scaling is useful for large and high definition images, but can affect the overall size of an image as displayed within first-click testing — due to this we recommend uploading images that are set to 72 PPI.

You can then click 'Select image' and write the task that goes with it. Or, you can keep uploading all the images you want to include in your study, and edit the title of each one. Then, when you get to the next task and click 'Upload an image', you can select the 'Images' tab and simply choose the one you want to work on next.