would any of you kind folks be able to tell me how to resize an image to suit the upload requirements of the galleries here-like how to i get an image to be 512kb and it not ending up small and blurry?

First render as a tif file in any size up to 1040 pixels width.  Open in photoshop or PSP, and do whatever postwork you want, if any, and resave as a jpg.  On the jpg settings, DO NOT SAVE at maximum auality, but somewhere between High and medium.  After that, upload shouldn't be a problem.
DPH

thank you for your reply,i'll give that a shot tomorrow some time!

Depends on what program you are using.

In Paintshop Pro, do the following:

1.  File

1. Export

2. JPEG Optimizer

3. Ignore the "Wizard" button in the lower left of the next window. Instead adjust the compression dial.  The original image shows in the left window, the resulting image from the compression value you selected shows in the right window.  Magnify the image once if needed, but no more because you are concerned about the overall appearance of the image, not each pixel.

Lower number equals better image quality but a larger file size. Higher number equals reduced image quality but a smaller file size.  Play with the dial until you get your image size under 512 KB   [524288 bytes] while maintaining the best possible image quality that you can. The perfect balance is if you get the compression number to give you a file size under 512 KB with no visible reduction of image quality.   Between 0 and  20 usually works well. After that loss of quality is usually noticable.

If you notice that you are having to use too high of a compression value and that the image quality is becoming noticably reduced,  exit from the jpeg optimizer . You will need to reduce the dimenstional  size of your image.  But don't do it through "Resizing"  because the image quality will often be reduced and using bicubic resampling and sharpening doesn't always preserve the quality. Not to mention you will be double compressing it which will result in even poorer quality.

 Instead do the following to reduce the size of the image:

A)  Selections / Select All
B) Selections / Modify / Contract = X number of pixels IE: 10 (equals 20 pixels in both height and width)
C) Image / Crop to Selection

Then go back and do the JPEG Optimizer again (again ignore the Wizard button).

Once you have your file size 512 KB or less and have maintained a good image quality, save the image.

You can do the same thing in Photoshop but you have to go to "File" and "Save to Web" and it's pretty much the same thing.

As for saving a thumnail...

1. Create a new blank image 200 x 200 pixels
2. Select your gallery image and "Copy"
3. Select your blank thumbnail image and "Paste" the gallery image into it as a "New Layer". It will be much too big, but don't worry about the parts that are not showing, they will be removed when you save the image later.
4. Move the image around inside the thumbnail image until you get a preview that you like.
5. Save it using the same technique as above  in order to get the file size less than 15 KB   [15360 bytes].

You will always end up with crisp clear gallery images and thumbs.

I always save my render as a jpg at 100% quality & they are larger than 1024 pixels. The file size is still small enough to post in the galleries here. I can't understand why you would need to reduce a picture in size or quality, one of my images here is 1292 x 1637 at full jpg quality & is only 169kb. I save my images in Paint Shop Pro.

It largely depends on the image itself. Bolder, brighter colours and addition of textures etc will increase the pixel count and cause the file size to increase.  I've had some .jpg images save within the 512 KB limit with zero compression (mostly my unframed images).  But I've also had some (usually the framed images)  where I've had to compress with a value of 10 or even 15 in order to squeak in under the 512 KB size limit.

i appreciate the time and effort of you guys replying, it has helped me with some theory practice on jpeg compression and image quality, i've managed to get an image up now, my first post to renderosity,
thanks all cheers!

I open my renders (1280X1024 4800dpi) in Corel Paint and save them as .jpg files for uploading.  I usually use a compression percentage of about %7 to get it to the required limitations.  There is a minimal amount of degradation but nothing so bad as making it too ugly to post.  I leave my lack of talents to that department.