Chrome

In Chrome, hold down Control + Shift + Delete on PC (Command + Shift + Delete) or go to the Three Dots icon in the top right corner

then go to Clear Browsing Data.

On this window change your time range to All time, check only Cached images and files and then hit Clear Data.

Edge

In Edge, hold down Control + Shift + Delete or go to the Three Dots icon at the top right corner of the window, then go to Settings.

In Settings, select Privacy, Search, and Services. Scroll down to Clear browsing data and select Choose What to Clear. 

Ensure that Cached images and files is selected. You may deselect the other items if you'd like to only clear your cache. Select Clear Now to clear your cache. 

FireFox

In FireFox, select the hamburger icon (three lines) in the upper right corner of the page to open the mini-menu. Select Settings.

Select Privacy & Security and scroll down to Cookies and Site Data. Select the Clear Data... button.

In the Clear data pop-up window, ensure that Cached Web Content is checked. You can optionally uncheck Cookies and Site Data if you'd like to only clear your cache. Then select Clear. 

Safari

To empty Safari’s browser cache, you’ll need to enable the Develop menu by selecting Safari > Settings > Advanced and checking the Show features for web developers box.

Then, you can go to Develop > Empty Caches