Hi grbalabanis,
In WordPress 5+ version you can easily use the Image block of Gutenberg feature. On Page/Post Editor page you can use the ‘Image’ under the ‘Common Blocks’ and upload or select the image. After adding image you will see the link button on Tool Bar on same image editor box where you can set the URL link.
For the Classic Page Editor you can add the image through Add Media button on Tool Bar and after selecting the Image at the same dialogue box you will find ‘Link To option’ where you can choose Custom URL option and set the URL Link.
Thanks