Step 1: Copy the link/URL of the YouTube video of which you need to download thumbnail images.
Step 2: Click here or navigate to https://www.newgenentertainments.com/thumbnail-downloader.
Step 3: Paste the YouTube video link and click submit.
Step 4: The thumbnail images of different quality like HD, HQ, 1080p, 4K of the video are displayed.
Step 5: Right click on the image and select "Save as" to download the image file or if you are using touch screen, long press on the image and click "Download image."