Height of Slider Changed

When I first activated the Activello theme, it all looked great and the header was just in the demo. Then, I added a few plugins and suddenly when I came back to it, the header/slider was reduced in height, which looks pretty bad as all photos are now cut off and in some there are people - before the strange change their heads were visible now all cut off at the neck.
How can I get the original height of the slider back?
I played around with having less menu’s and less posts on the front page because I thought initially it might have been a space problem but it didn’t help.
What can I do to get the default header/slider size back?
And no, it has nothing to do with the size of the actual photographs…as it was fine initially!
I would provide url but my website is not live yet as I am migrating it over to another host.

Hi @tamarascharf,

I hope you are well today and thank you for your question.

Could you please provide me the screenshots of how it’s displaying now and before so that i can better understand the situation and help you?

Kind Regards,
Movin

Thank you for your help. Actually some of this has resolved due to me adjusting a plugin that was messing with my images - the heads are not cropped anymore.
However, I am still experiencing problems with the slider…
The site is live now so you are able to see for yourself. Some of the images in the slider are narrow, others way too wide, which causes the site to ‘jump’ when you try to read something. I am thinking I will have to crop all featured images to fit a certain dimension to look uniform and good in the slider, and stop the site text from jumping when the photo changes?
Please take a look so you see what I mean: www.tamarascharf.com

I am thinking I will have to crop all featured images to fit a certain dimension to look uniform and good in the slider, and stop the site text from jumping when the photo changes?

Yes you are right. The images should be at least in size 1920px X 550px or greater than it but in the same ratio.