Corrupted jpegs, and windows scrolling by themselves

[Sproo]

Here's a list of odd occurrences in photo-filled directories, which
someone should shed some light on.

* Some downloaded jpegs show a normal thumbnail, but large chunks are
missing when the
image is viewed at a larger size. How is the thumbnail being
generated so that it
interpolates sensibly across the missing areas? Or are those areas
actually encoded in the
file but for some reason not being displayed when the image is shown
at a larger size?
* Some downloaded jpegs likewise show a thumbnail, but the image is
actually rotated or
cropped relative to what the thumbnail shows. How is this possible?
The thumbnail
sometimes seems to have extrapolated beyond the image. I can only
assume that the
image encoded is a larger version of what the thumbnail shows, but
the previewer is rotating
and cropping it automatically for some reason (even when not told to
rotate, and told to
zoom out fully).
* Some downloaded jpegs show a garbled (colorful static) thumbnail, but
an intact image in
the previewer. The explorer command "refresh thumbnail" to manually
regenerate the
thumbnail corrects the problem, but renaming or moving the file (or
any parent directory)
causes explorer to regenerate the thumbnail again. Every time the
thumbnail is regenerated
it toggles between static and normal, so after being static, it
becomes normal when you
manually refresh, only to become a colorful hash again on being moved
or renamed, normal
again when manually refreshed, etc...Somehow, it is not simply
generating the thumbnail
from the full-size image in a deterministic fashion, but in a manner
that involves some sort of
"memory", or involves the pre-existing thumbnail as well as the
full-size image. If that
thumbnail is mangled the result is normal and vice versa. Strange!
* For some reason, just as I finished the above item, this bulleted
list suddenly reformatted
itself and the neat left side got all mangled. Google groups bug?
It's as if the word wrap
column spontaneously decreased by a few characters.
* At one point today, I went to a directory with around 4000
photographs, located and
selected one, and then alt-tabbed to a different explorer window. In
this window I navigated
to a directory where I intended to place the selected photo. When I
tabbed back to the first
window, it was displaying the top of the list of files, there was no
selection, and the files
were arranged alphabetically, none of which had been true before.
This happened while the
window didn't have focus. Who did this, and how? Someone evidently
deselected files,
selected "Arrange by -> name" from the view menu, and scrolled the
window all the way
upwards, but it wasn't me and there's no remote login capability on
this box. System
checks clean of viruses, spyware, trojans. How the hell was this
done? Or have I
encountered a bug in explorer where directories full of jpegs in
thumbnail mode will
spontaneously accept ghostly user-input when they're supposed to be
idle or even
minimized?

 

[John Inzer]

Here's a list of odd occurrences in photo-filled
directories, which someone should shed some light on.

* Some downloaded jpegs show a normal thumbnail, but
large chunks are missing when the
image is viewed at a larger size. How is the thumbnail
being generated so that it
interpolates sensibly across the missing areas? Or are
those areas actually encoded in the
file but for some reason not being displayed when the
image is shown at a larger size?
* Some downloaded jpegs likewise show a thumbnail, but
the image is actually rotated or
cropped relative to what the thumbnail shows. How is
this possible? The thumbnail
sometimes seems to have extrapolated beyond the image. I
can only assume that the
image encoded is a larger version of what the thumbnail
shows, but the previewer is rotating
and cropping it automatically for some reason (even when
not told to rotate, and told to
zoom out fully).
* Some downloaded jpegs show a garbled (colorful static)
thumbnail, but an intact image in
the previewer. The explorer command "refresh thumbnail"
to manually regenerate the
thumbnail corrects the problem, but renaming or moving
the file (or any parent directory)
causes explorer to regenerate the thumbnail again. Every
time the thumbnail is regenerated
it toggles between static and normal, so after being
static, it becomes normal when you
manually refresh, only to become a colorful hash again
on being moved or renamed, normal
again when manually refreshed, etc...Somehow, it is not
simply generating the thumbnail
from the full-size image in a deterministic fashion, but
in a manner that involves some sort of
"memory", or involves the pre-existing thumbnail as well
as the full-size image. If that
thumbnail is mangled the result is normal and vice
versa. Strange! * For some reason, just as I finished the
above item, this bulleted list suddenly reformatted
itself and the neat left side got all mangled. Google
groups bug? It's as if the word wrap
column spontaneously decreased by a few characters.
* At one point today, I went to a directory with around
4000 photographs, located and
selected one, and then alt-tabbed to a different
explorer window. In this window I navigated
to a directory where I intended to place the selected
photo. When I tabbed back to the first
window, it was displaying the top of the list of files,
there was no selection, and the files
were arranged alphabetically, none of which had been
true before. This happened while the
window didn't have focus. Who did this, and how? Someone
evidently deselected files,
selected "Arrange by -> name" from the view menu, and
scrolled the window all the way
upwards, but it wasn't me and there's no remote login
capability on this box. System
checks clean of viruses, spyware, trojans. How the hell
was this done? Or have I
encountered a bug in explorer where directories full of
jpegs in thumbnail mode will
spontaneously accept ghostly user-input when they're
supposed to be idle or even
minimized?

=======================================
Just a guess, but it sounds like you
may have a corrupted user WinXP
user account.

--

John Inzer
MS Picture It! MVP

Digital Image
Highlights and FAQs
http://tinyurl.com/aczzp

Making Good Newsgroup Posts
http://www.dts-l.org/goodpost.htm

 

[Sproo]

I'd damned well better not. This happens when logged in as
administrator, too, and if that account is corrupt, God help me.

 

[John Inzer]

I'd damned well better not. This happens when logged in as
administrator, too, and if that account is corrupt, God
help me.

=================================
Well as I said...it was just a guess.

Maybe you could create a new user account with
administrative priveledges and see if it has the
same issues you are currently experiencing.

And it may be worth a trip to your local computer
sercive center.

Maybe these articles would be useful:

(279783) How To Create and Configure
User Accounts in Windows XP
http://support.microsoft.com/?kbid=279783

(811151) How to Copy User Data to a New
User Profile
http://support.microsoft.com/?kbid=811151

--

John Inzer
MS Picture It! MVP

Digital Image
Highlights and FAQs
http://tinyurl.com/aczzp

Making Good Newsgroup Posts
http://www.dts-l.org/goodpost.htm

 

[Sproo]

I honestly don't think this is a user corruption issue. I've seen the
same symptoms with an older system -- XP but not media center edition.
And XP SP1 before SP2 came out. I've had Explorer windows that didn't
have focus spontaneously scroll up, deselect items, and change sort on
that system as well, and I think I even saw that behavior when the
current OS version was Windoze 98(!). All suggestions of hacking aside
I think these are simply bugs in Explorer -- long-standing ones, going
back at least one service pack in the case of the thumbnail wackiness
and spanning the DOS/NT kernel divide in the case of the other
bogosity. The latter seems to be triggered fairly often by closing or
changing directories in a different Explorer window.

As for the former, I just ran across an image whose thumbnail
representation didn't contain some scribblings that showed up in the
previewer. The scribblings weren't thin lines that disappeared when
Explorer sampled the image down to create a thumbnail. They were fairly
thick lines and whole areas painted in. There is no logical way
Explorer could have missed them in generating the thumbnail. But there
was an image in the same directory, identical save for the lack of
scribbles, and with the exact same thumbnail, which gives me a good
clue as to where Explorer got the thumbnail from. Unless we are to
believe Explorer can sometimes make up thumbnails out of whole cloth,
or somehow see the whole edit history of a file, even a
freshly-downloaded one on a system that doesn't use a journaling
filesystem, we must conclude that sometimes the thumbnail it generates
for file A comes from downsampling file B with B occasionally not equal
to A. This is a bug, pure and simple. Now, does anyone know
fixes/workarounds? Both of these Explorer oddities have survived a
sizable number of patches and updates and whole service packs, so it
looks like MS has no intention of addressing either issue, which leaves
it up to the community to develop and to make widely known workarounds
(or even patches, like the widely-available half-open connection limit
patch).