One of the most popular image/gif sharing site Imgur seems to be one of those well known sites that has also quite some claims of malicious content around the net. Most of these user reports are seemigly based on harmful advertisements within the site, but some comments also report about malicious redirects and even possibility of some of media content uploaded to the site containing malicious stuff etc. I’m not personally sure how viable claims like these are, since most of them are reports from at least two years back, but while most of site scanners show site being clean from malware, some sources like Google Safe Browsing and Virustotal IP scan warn about possible malicious content.
https://www.virustotal.com/en-gb/ip-address/23.235.40.193/information/
https://www.google.com/transparencyreport/safebrowsing/diagnostic/index.html#url=imgur.com