Yes, you are correct, it blocks almost all images on daily mail - let me explain you what happens here.

The primary goal of this extension is to give you the control to be able to block or allow scrips on specific websites. You don't have any other control without extensions with your stock browser but turning off scripting entirely for every pages. That's not useful though, hence my development.

Daily mail loads images using scripts and this is a tendency where the industry go. However pushing functionality from server side back to the users (by running scripts on their computers instead of on the server) uses much more resources on the users' devices and so their battery go off much faster. This is one problem, and the other is that websites and web services become more and more vulnerable for hacker attacks (using cross site scripting and many other technics).

I'm not saying you should turn off scripts on all sites because it might break functionality of it. However if you don't trust some site or they use heavy scripting making your device slow or you worry about being hacked through that site, then it is a good practice to block scripts from that site if you want to visit it anyway.

So this tool is just an option for you that the stock browser does not offer. There are other options for you like using NoScript extension but teaching your browser for every domain for every script calls seems a tedious and long work. It varies whom it's worth it to.

So you have several options to solve a problem if one arises, it is up to you which one fits you the most. These options might not be perfect but it's better to have more than less.

Regarding the original YesScript, I don't know what it does under the hood because I did not study its code thoroughly but instead I've rewritten mine entirely on my own. But as far as I know it should do the same like blocking a web site's scripts entirely. But if you say that it lets the images load for Daily mail, then it may block scripts belonging only to the original domain and not blocking all of them. If that's the case (I don't know) then my version may give better security and save more resources. But I have to say that the developer made a really nice work creating it in my opinion.

I'd also like to mention that one of my other priority when writing this extension was to create an extremely small code set so it can be audited much easier making it more trustful. The less lines of code, the more reliable and secure a solution can be. Currently the main code consists of 81 lines only.

Thank you.