Probably DVD size. They might start to get blurry at 1280x720 project size but it's worth a try.

Thanks guys, I had no idea. I've never used anything that small. Almost all stills that I have used in the past were between 1.5 and 4MB. On a side note, why do some pictures have the same 'dimension' but the 'size' in MBs is different? Thanks again. Cin

Depends on how much the image has been compressed. It is called compression ratio.

An image with a 5:1 compression ratio will be 5 tomes smaller than uncompressed.

Almost all stills that I have used in the past were between 1.5 and 4MB.

It's the pixel image size that counts, not it's compressed storage file size, although the degree of compression will affect the image quality.

I have the next way of working with these that suites me the best.
When you are working on a project, that project has already certain dimensions f.i. HD 1920x1080 pixels.When you add a pictures that has other dimensions it suites not that of the project. For this Vegas has for long time an option to set it right from the moment you add the picture.
That option is in Options/Preferences/Editing (1 on the screenshot), That option make in the Pan/Crop (2) the right dimensions for your present project.
You are still able to arrange the right look with the pan/crop options to move that pan/crop box(3)

When the picture becomes by this too blurry I delete it and use another one.

Will they look 'right' in a DVD project? Blu-ray? Is there a rule of thumb that tells you what size will look good in a project?

Rule of thumb:

1. A Picture with the same resolution as video project will keep it's quality.
2. A Picture with a lower resolution as video project will keep it's quality, but looks bad because Vegas resizes/enlarges picture to project size.
3. A Picture with higher resolution as video project will loss it's quality, but looks good because Vegas resizes/downscales picture to project size.

Almost all stills that I have used in the past were between 1.5 and 4MB.

It's the pixel image size that counts, not it's compressed storage file size, although the degree of compression will affect the image quality.

Yes, it is confusing to compare because the unpacked (8bpp) uncompressed image size will be hidden to the editor unless they dig for the information. A 50 MB compressed file may contain essentially all of the information when unpacked to 200 MB for editing.

     Thank you guys for all the information, and thank you j-v for the picture. They are definitely worth a thousand words in my world!  ;) I guess I got confused by the fact that my computer makes thumbnails all the time for stuff and they are in the kb range and I also know they are very tiny and wouldn't be a good size for a project. After work today I'm going to take a dozen or so and burn them on a DVD just to see for myself what they will look like. Thanks again. Cin

After work today I'm going to take a dozen or so and burn them on a DVD just to see for myself what they will look like.

+1

DVD resolution is 720x480, so any image that resolution or greater will look just fine, make sure you burn it in a progressive scan format, not interlaced.

Thank you Fr0sty for your response. So resolution=dimension? And if resolution is all that matters is there any point in having a larger file? I thought the larger the file, the better the quality? Thanks, Cin

Yes, resolution = dimension e.g. 720 pixels by 480 pixels. But file size affects the quality of the image carried by those pixels. The greater the compression the greater the quality loss. Greater compression = smaller files, less compression = larger files. You need to find a balance that suits you. Using jpg or png for your images even small compression produces files much smaller than an uncompressed file. With jpg I use 95% quality i.e. only 5% compression.

Greater compression = smaller files, less compression = larger files.

Depends also on the kind of picture, a graphic, like a logo, with a few colours and less details can be a very small file. Because the compression can also be very effective and doesn't mean automatic quality loss. The same counts for video.