YouTube - How To Upload Custom Thumbnails

Each time you upload a video, YouTube automatically generates a set of three thumbnails for you to choose from. You can stick with YouTube's proposals or upload a custom thumbnail, preferably a beautiful picture or photo you have prepared beforehand. 

Prerequisites

- The popular image formats (optimized for the web) are supported: JPEG or PNG. 
- The maximum file size is 2MB. 

Upload your thumbnail

Sign-in to your YouTube channel and then open the Creator Studio > Video Manager > Videos: 

Select the desired video and then click on the Edit button > Info and Settings tab: 

Click on the Custom Thumbnail button displayed, browse for the image you want to use and click on Save changes: 

How to Block a User on YouTube

Someone keeps posting pesky comments on your YouTube channel? This guide explains how to block undesired users on YouTube: 

Click on the user's name to access his channel homepage. Navigate to theAbout tab, click on the Flag menu and then select Block User from the list:

YouTube displays a small warning message: Are you sure you want to block this user?. Click on Submitto proceed: 

That's it; the blocked user won't be able to contact you through private message or comment on your channel.

Download the MP4 Version of the Videos Published on Your YouTube Channel

You want to download a video published on your YouTube channel for offline editing? You want to upload the video on another streaming platform? Here's a simple trick to retrieve the MP4 version of videos published on your YouTube channel without the need for you use any third party software. The procedure is as follows: 

Sign-in to your YouTube account and click on your profile picture located top-right > Creator Studio. Go to the Video Manager section and select the desired video. Click on the small arrow next to the Edit button and then select Download MP4

Select the location to save the file and then click on OK.

Download MP3 files from youtube(easy online way)

Here is a easy way to convert and download mp3 files from youtube