Actually I did install an upgrade yesterday (webmail 5.1.4) and then 
after that, I manually installed the new image files.  So what 
happened was the old ones got cached in the default /static folder and 
when I purged the configured cache folder, it was too late.  Thanks 
for your help.  I will make a note to purge both folders every time.   
I only noticed this because I found a post about someone complaining 
about the static folder being used even though they have configured a 
cache folder.

This is exactly what we do, just that you didn't install an upgrade.

Michael, thank you for forcing me to dig deeper.  I found the reason 
why manually updating these files didn't help.  Apparently, even 
though I was purging all of my cache files from the configured horde 
cache directory, there were still some cache files located in the 
default horde cache directory /horde/static that were there from the 
initial install.  Once I purged these too, then the new files I 
downloaded manually resolved the problem.

Perhaps there should be a process that forces a purge of all caches in 
both places each time an upgrade is installed to help reduce these 
types of problems.  In any case, I will add this to my 'to do' list 
after an upgrade.  Thanks.

This fix is in Horde_Core 2.12.0, which hasn't been released yet.

I can't provide support if you are patching locally other than that I 
can verify that this change fixes.

I manually downloaded and replaced the corresponding 4 files that were 
updated and removed the ajax-loader.png file that was deleted, purged 
the cache and restarted the server but the buttons still appear 
incorrect when using a mobile device using different browser versions. 
  Am I missing something?

Changes have been made in Git (master):

commit 4f6a8acee3eafbce6137dcc7224aa32d07af3c3b
Author: Michael M Slusarz <slusarz@horde.org>
Date:   Fri Dec 6 22:03:04 2013 -0700

     [mms] Fix jquerymobile icons (Bug #12876).

  .../Core/js/jquery.mobile/images/ajax-loader.png   |  Bin 340 -> 0 bytes
  .../js/jquery.mobile/images/icons-18-black.png     |  Bin 1767 -> 1768 bytes
  .../js/jquery.mobile/images/icons-18-white.png     |  Bin 1806 -> 1795 bytes
  .../js/jquery.mobile/images/icons-36-black.png     |  Bin 3611 -> 3827 bytes
  .../js/jquery.mobile/images/icons-36-white.png     |  Bin 3648 -> 3827 bytes
  framework/Core/package.xml                         |    8 ++++----
  6 files changed, 4 insertions(+), 4 deletions(-)

http://git.horde.org/horde-git/-/commit/4f6a8acee3eafbce6137dcc7224aa32d07af3c3b

Changes have been made in Git (master):

commit 46e7a9b05c485b87eb959eccbd9953364ba5fb5e
Author: Michael M Slusarz <slusarz@horde.org>
Date:   Fri Dec 6 22:03:04 2013 -0700

     [mms] Fix jquerymobile icons (Bug #12876).

  .../Core/js/jquery.mobile/images/ajax-loader.png   |  Bin 340 -> 0 bytes
  .../js/jquery.mobile/images/icons-18-black.png     |  Bin 1767 -> 1768 bytes
  .../js/jquery.mobile/images/icons-18-white.png     |  Bin 1806 -> 1795 bytes
  .../js/jquery.mobile/images/icons-36-black.png     |  Bin 3611 -> 3827 bytes
  .../js/jquery.mobile/images/icons-36-white.png     |  Bin 3648 -> 3827 bytes
  framework/Core/package.xml                         |    8 ++++----
  6 files changed, 4 insertions(+), 4 deletions(-)

http://git.horde.org/horde-git/-/commit/46e7a9b05c485b87eb959eccbd9953364ba5fb5e

Horde_Core 2.11.2.

Changes have been made in Git (master):

commit 4f6a8acee3eafbce6137dcc7224aa32d07af3c3b
Author: Michael M Slusarz <slusarz@horde.org>
Date:   Fri Dec 6 22:03:04 2013 -0700

     [mms] Fix jquerymobile icons (Bug #12876).

  .../Core/js/jquery.mobile/images/ajax-loader.png   |  Bin 340 -> 0 bytes
  .../js/jquery.mobile/images/icons-18-black.png     |  Bin 1767 -> 1768 bytes
  .../js/jquery.mobile/images/icons-18-white.png     |  Bin 1806 -> 1795 bytes
  .../js/jquery.mobile/images/icons-36-black.png     |  Bin 3611 -> 3827 bytes
  .../js/jquery.mobile/images/icons-36-white.png     |  Bin 3648 -> 3827 bytes
  framework/Core/package.xml                         |    8 ++++----
  6 files changed, 4 insertions(+), 4 deletions(-)

http://git.horde.org/horde-git/-/commit/4f6a8acee3eafbce6137dcc7224aa32d07af3c3b

Since the last few minor releases of IMP, when you login using the 
smart mobile interface, most buttons do not appear properly.  To be 
clear, the button itself is fine but some buttons have a small circle 
on them where inside the circle, an icon appears.  For example, in the 
inbox view, at the bottom ,the Refresh and Search buttons or at the 
top, the Folders and Logout buttons have small circle where an icon 
appears within.  These all have either nothing in them now or the icon 
within the small circle is not centered in the middle of the circle.   
For for the Search button, instead of a magnifying glass, you see a 
few dots on the left side of the circle.  The Folders button is 
completely empty on the circle.  Similarly, on the right of each mail 
item in the inbox is a circle but it now is completely grey inside 
with no icon (normally >).  The same is true on the login page.

I have confirmed this with various brand phones both apple and 
android.  I have not tried a tablet.  When I login using a desktop 
computer and the mobile interface, the buttons all appear correctly, 
although, on some buttons, the icon in the circle is not fully centered.

Thanks.