Want to Host a File?

You may want to host or send images/files.

Hosting a file means that you want to access it in the future. These files are usually kept on the website's servers for a long time. Example: You want to host an image so you can link it in a forum post.
Sending a file means that you want to send it to another person's email so they can download it. These files are usually wiped from servers on a regular basis. Example: you want to send someone the Type Moon Encyclopedia pdf.

Here are some recommended services:

Images:
Postimage: http://postimage.org/faq.php

Files:
Solid Files: https://www.solidfiles.com/ - Sweden based, minimalist design
Zippy Share: http://www.zippyshare.com/ - Host files up to 200MB
Sendspace: https://www.sendspace.com/ - Send files up to 300MB
Tiger Files: tigerfiles.net/en - Host files up to 100MB
TusFiles: https://www.tusfiles.net/ - Host files up to 600MB for 30 days. (At the download link they try to force you to use their accelerator. Uncheck the option first)
File Dropper: http://www.filedropper.com/ - Host files up to 5GB (not tested) for up to 30 days
Users Cloud: https://userscloud.com/ - 1GB file size, not really sure about the rest

Test

https://www.phpbb.com/support/docs/en/3.0/kb/article/how-to-create-a-style-basics/
http://testerplease.prophpbb.com/

Pomf.se clones and File Uploading comparison - https://docs.google.com/spreadsheets/d/1kh1TZdtyX7UlRd55OBxf7DB-JGj2rsfWckI0FPQRYhE/edit#gid=0

BONUS:

Archive webpages with https://archive.org/web/ or http://archive.is/