Image Slider killed everything

Experienced web person here - trying a Concrete5 project for the first time:
- I tried uploading pngs through the media manager - file sizes show as 0KB, but previews display;
- I decided to try "Image Slider" content module, placed it on a page, added the first image - and the entire system died. I see a 404 style page that says "An unexpected error occurred.
Class 'finfo' not found". And a button "Back to home" that is unresponsive.

I try to go back to the dashboard, to the login - nothing. The same error page and no sign of life.

Anything I can try?

View Replies:
mlocati replied on at Permalink Reply
It seems that you are missing the fileinfo PHP extension.

More details about how to enable it here:
adminganush replied on at Permalink Reply
Thank you!