Ok so your pretty sure you don't have the ability to create thumbnails in Moveable Type, but you wanna. Well you've come into the same problem as me, lucky for you though I am gonna tell you how to install a thumbnailer.
Chances are if you go to SixApart they'll tell you to use Image::Magick. Forget THAT! A thumbnailer is a thumbnailer. In this situation we are gonna use something called Netpbm. Now again normally your hosting service should have this already but we're gonna assume they don't. This is gonna be a straight up local install on your own server space.
1.) Get the info you normally have to upload stuff
(ftp address, login name, password, etc)
2.) Find your
mt-config.cgi file on your server somewhere.
(Note: I found mine in the /cgi-bin/mt)
3.) When you find the .cgi file you will need to open, edit and save it. Make sure the lines changed look like what is below:
#
# Specifies the image toolkit used to create thumbnails from uploaded images.
# By default, the ImageMagick library and Image::Magick Perl module are used;
# if your system does not have these, you can use the NetPBM tools instead
# (assuming that your system has these tools installed). Possible values for
# this setting are "ImageMagick" or "NetPBM".
ImageDriver NetPBM
#
# By default, Movable Type looks for the NetPBM tools in three locations:
# /usr/local/netpbm/bin, /usr/local/bin, and /usr/bin. If your
# NetPBM tools are installed in a different location, you can adjust the
# NetPBMPath configuration setting. Note that this path should be the path
# to the directory containing the NetPBM binaries; for example, if your
# pnmscale binary is at /home/foo/netpbm/bin/pnmscale, you should
# set the value of NetPBMPath to /home/foo/netpbm/bin.
NetPBMPath /home/whateveryourusernameis/netpbm/bin
#
(Note: whateveryourusername means put whatever your ftp
login user name is so if it's bob put:
/home/bob/netpbm/bin)
4.) Ok so save your config file and upload it back to where it was. Make sure permissions are 755 on that file, or in other words the following:

5.) Ok so you got your config settings ready for NetPBM. Now you you gotta upload the actual netpbm folder.
Right click here and select "Save target as" to download the netpbm.zip to your computer
6.) Unzip the .zip file you just downloaded
7.) Upload the actual netpbm onto your server. In this case I uploaded it to my cgi-bin folder inside a folder I called mt. Basically upload the whole folder into the same folder your mt-config.cgi file was.
8.) Make sure the permissions for the netpbm folder were set correctly. 755 is what all the folder's permissions should be set as.

This is the MOST important step. If your permissions aren't set right on these files it will screw up.
(Note: Usually on ftp programs and even in Windows FTP functionality it will let you right click on the folder and select 'Properties' and from there you should see somewhere where you will be able to set permissions. I think in IPswitche's software it's CMOD, I think)
9.) Ok you got it uploaded? Good. Log in to MT Admin setup. Just for the heck of it, create a new entry and select Upload File on the left side under Posting. Find whatever image you wanna test. Once you select it, hit the Upload button. The next screen you see should look something the following:

10.) Congrats!! You did it. From here you can pretty much play around with it and figure out whatever.
WAIT WAIT!!! I didn't get that screen.
11.) If the thumbnail options didn't magically appear like it should have, don't worry the same thing happened to me. There is one last folder you need to upload, the IPC folder
Right-click, 'Save target as', and save it
12.) This time when you unzip and upload you wanna upload the whole IPC folder into your extlib folder. In my case the pathway was as follows: /cgi-bin/mt/extlib/
13.) Now you should be able to upload this file with no problems, the permissions should even be correct. If you do have problems though check back and double check that folder's file permissions look like 755

14.) Repeat step 9.
15.) OK NOW YOU'VE DONE IT WOOOO WHOOOO.
16.) Huge Props to the SnipTools tutorial which pretty much explains this whole thing in greater detail. If you wanna see the instructions I referred to along the way go to the following link:
SnipTools Tutorial