As far as images that a modern browser can display, JPEG was created in 1992 and GIF in 1987, so there isn't going to be much prior to that. HTTP and Gopher date back to 1991, so the oldest image online that still resides at its original location would be on an FTP server.
Here's one of the oldest I can find, with timestamp 1988-07-06 00:00:
ftp://ftp.sunet.se/mirror/archive/ftp.sunet.se/pub/pictures/anime-manga/UruseiYatsura/Images/mendo.gif
or via http:
http://ftp.sunet.se/mirror/archive/ftp.sunet.se/pub/pictures...
This is the oldest one I can find on nic.funet.fi, from 1991:
ftp://nic.funet.fi/pub/pics/comp/net/misc/dnesu.gif
They have mirrors of many of the old ftp servers of yore, so if there's an older image out there, that's the place to look:
http://www.nic.funet.fi/pub/mirrors/
Most of the other old FTP servers I remember (sunsite.unc.edu, ftp.simtel.net, ftp.uu.net) have long since shut down. The ftp server at ftp.sunet.se is one of the oldest still running. Perhaps someone else knows of an older one?
I tried to find a copy of lena.bmp/lena.tga/lena.pcx since those file formats pre-date GIF, but I came up empty.
Here's one of the oldest I can find, with timestamp 1988-07-06 00:00:
ftp://ftp.sunet.se/mirror/archive/ftp.sunet.se/pub/pictures/anime-manga/UruseiYatsura/Images/mendo.gif
or via http:
http://ftp.sunet.se/mirror/archive/ftp.sunet.se/pub/pictures...
This is the oldest one I can find on nic.funet.fi, from 1991:
ftp://nic.funet.fi/pub/pics/comp/net/misc/dnesu.gif
They have mirrors of many of the old ftp servers of yore, so if there's an older image out there, that's the place to look:
http://www.nic.funet.fi/pub/mirrors/
Most of the other old FTP servers I remember (sunsite.unc.edu, ftp.simtel.net, ftp.uu.net) have long since shut down. The ftp server at ftp.sunet.se is one of the oldest still running. Perhaps someone else knows of an older one?
I tried to find a copy of lena.bmp/lena.tga/lena.pcx since those file formats pre-date GIF, but I came up empty.