CSS issues on purchased theme

Hi everyone,

I’m fairly new to this sort of thing (normally make do with whatever my preferred theme offers), but I have decided to branch out and have purchased a theme in order to improve my site and have some more flexibility.

The problem I’m having is that the images in my theme don’t resize to fit small and medium sized thumbnails and the homepage slider. Previous themes I’ve had did that with no trouble, but this time I’ve having terrible trouble.

I’ve had a look at the CSS but my brain seems to shut down whenever I even try and understand it.

My website is https://www.westhamworld.co.uk.

Currently, the slider images are resized to fit and then uploaded, which you can imagine is a real pain. You’ll also see that, in the latest post widget on the write, that the thumbnails don’t resize automatically, which again is a real problem.

At the moment, I’m having to upload three different sizes of the same image in order for it to all work. Can anyone correct this for me? I’m happy to hand over log-in details in order for some one to take a closer look.

Like I said, I’m new to all this CSS code and have no idea what I’m doing or where I’m going wrong. I ideally need something that works automatically for me so that I don’t get confused and frustrated (like I am now) and that I can publish news on the site quickly (very important).

Thanks in advance.