Hi @kanjijvoormij
I am sorry, we don’t have a bulk replace option, so you will need to open each slide of the slider one by one, and replace the images in your layers.
Note:
I checked your site, and I noticed that you use a lot of big images. ( I can see multiple images with 2MB and 3MB size. )
On page load, the browser needs to download at least 32MB of images which takes some time and will make your site and the slider load very slowly.
I would suggest optimizing the images both in file size and in quality, and that will improve the loading times a lot.
Here you can also find some extra tips that will help in improving the loading speed of both your site and your slider:
https://smartslider.helpscoutdocs.com/article/1925-how-to-speed-up-your-site
Best regards,
Laszlo.