Can I use the images appears in the actual demo theme? I’ve read the page I want to buy and I couldn’t found any mention.
It’s better to ask the author of the theme.
Many theme authors buy the images for their demos with a license that does not allow re-distribution, so I’m not sure those images can be used “as-is”.
If you ask the theme author, he/she will probably send you a link from where you can buy the images.
As an alternative, you can check the size of those the images and you can download similar images from websites which offer free images…
About which specific theme you are talking about ?
Please ask the authors of the theme. As hevada as said and i agree totally that there are many other who purchase images for their demos with a license that does not allow re-distribution
Or if you are looking forward to get paid images then you may purchase it from many online websites. Simply just google it and you can get many royalty free images