If you are having trouble with the HowTo: Create an image gallery using only CCK and Views instructions, here are some things to check:
A. Probably the first thing to do is check to see if Imagecache is creating the images. Look here in your site:
replacing 'Thumbnail' with whatever you call your thumbnail sized images.
Do you see image files in there? If so, Imagecache is working, if not:
a. Make sure you have clean URL's enabled:
b. Make sure your file system is set to public:
If that's all OK, and Imagecache is not working, not sure what to say.
If Imagecache is working:
B. I assume you did steps 1 and 2 correctly so that you have at least 2 Imagecache presets – one for display size image and one for your thumbnail size.
C. If you just look at one of the CCK image nodes you created and the correct (e.g. "display") size is not showing, go edit your CCK content type and make sure that the imagecache settings for the imagefield you added to that content type (step 4 above) are set to 'thumbnail' for 'Teaser preset' and 'display' for 'Body preset' (note you may call 'thumbnail' and 'display' something different). Here is where you are when you are doing this:
where 'image' is the name of your CCK content type for images and 'field_image' is the name of your imagefield.
I'll try to clarify this a bit more if I can. What you need to look at is the "Display" settings for the imagefield you added to the Image content type (keep an eye on the various tabs at the top of the page as you're working with CCK so you begin to learn where everything can be found at). You can find this at admin/content/types/image/display (if your content type is named Image). If you want, you can get to it via the menu by clicking Administer -> Content Management -> Content Types -> Image (click the name of your content type in the left column, e.g. Image) -> Display fields (click the Display fields tab at the top). You should now see a set of dropdown menus. You can set Label to Hidden, Teaser to Thickbox: squarethumbnail (the name of your Imagecache preset for thumbnails), and Full to Thickbox: display (the name of your Imagecache preset for images shown in the node view).
If the above looks OK, then the problem is probably not in the CCK area but in the Views area.
D. Check your View: Double check steps 5 b,c and d in the tutorial.
It's not mentioned in the HowTo, but you might want to set the "Maximum resolution for Images" at admin/content/types/image/fields/field_image (again, assuming the content type and field names used in the HowTo). I'd set this for something like 1024x1024 or something like that - this will ensure that if a user uploads a massive 3000x3000 (or whatever) photo, it will scale it down and store it at a size that's still large enough for any potential use you'd have for it, but not excessive and space-wasting.