It's a free tool that produces customized placeholder images (blank images) on the go, as shown in the following example
Input your desired size ( width x height) in this exact order like this:
you may change the palceholder background color as well as the text color, the defauts colors are :
both these colors can be customized as you like.
these are also customizable, as shown in the screenshot & choose various format for your placeholder( PNG,JPEG, GIF, WEBP), The Custom txt refers to the text inisde of the placeholder image usually shows the dimentions input in the size , but you can add custom text in the appropriet field to change it.
All you need to do is click on the copy botton & place it on your editor, or place it on your browser and download it and keep it safe somewhere to use it whenever you need it.