Imgur and Google Photos and similar image hosting / sharing sites are great for bells whistles buttons and general purpose use cases. But they re-compress and convert most if not all large >10 MB or >15 MB files and quality is lost. For example, Imgur converts AND compresses large >10 MB PNG to lower quality JPG. 
Thanks to fellow forum members here, I found ImgBB and ExtraImage. These sites respectively will allow 16 MB and 20 MB file uploads and they maintain original file format, size and quality.
ImgBB -- https://imgbb.com and ExtraImage https://extraimage.net
Please add good free lossless image hosting websites in your comments below.
Here are sample snapshots in PNG format from 4k video of my Eken H8 Plus. Note: files were lossless re-compressed in IrfanView and PNG-Optimizer. * Click on the small photos to see large 8 MP photos.


-- more hi-res samples in this album - https://extraimage.net/album/2xb - and in this album - https://extraimage.net/album/Naw
*UPDATE*
Also, BAYIMG -- http://bayimg.com/ -- lossy100 MB single image upload. Or upload multiple images in a ZIP file 100 MB to make an album. PNG images and large images are converted to JPG.
-- here are samples -- http://bayimg.com/album/OAAOHAAac
*UPDATE*
Also, Photoland.io -- https://photoland.io -- lossless 25 MB uploads without registration/login, and 128 MB uploads with registration / login.
*UPDATE*
Also, GIFYU - https://gifyu.com/ - lossless 100 MB uploads
*UPDATE*
LensDump - https://lensdump.com/ - lossless 100 MB uploads. requires users to sign-in.
*UPDATE*
PicHub - https://pichub.site - lossless 50 MB uploads.

Thanks to fellow forum members here, I found ImgBB and ExtraImage. These sites respectively will allow 16 MB and 20 MB file uploads and they maintain original file format, size and quality.
ImgBB -- https://imgbb.com and ExtraImage https://extraimage.net
Please add good free lossless image hosting websites in your comments below.
Here are sample snapshots in PNG format from 4k video of my Eken H8 Plus. Note: files were lossless re-compressed in IrfanView and PNG-Optimizer. * Click on the small photos to see large 8 MP photos.


-- more hi-res samples in this album - https://extraimage.net/album/2xb - and in this album - https://extraimage.net/album/Naw
*UPDATE*
Also, BAYIMG -- http://bayimg.com/ -- lossy100 MB single image upload. Or upload multiple images in a ZIP file 100 MB to make an album. PNG images and large images are converted to JPG.
-- here are samples -- http://bayimg.com/album/OAAOHAAac
*UPDATE*
Also, Photoland.io -- https://photoland.io -- lossless 25 MB uploads without registration/login, and 128 MB uploads with registration / login.
*UPDATE*
Also, GIFYU - https://gifyu.com/ - lossless 100 MB uploads
*UPDATE*
LensDump - https://lensdump.com/ - lossless 100 MB uploads. requires users to sign-in.
*UPDATE*
PicHub - https://pichub.site - lossless 50 MB uploads.
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