When I try to "save for web" my work in Illustrator (258px - 170px) it shows the right image size (258px - 170px) but after I save the image, and open it in windows, the image is really small. When I zoom in, it blurs so something is wrong. What am I doing wrong? How can I save without getting my image so small?
Not sure what version of Illustrator you are using, but make sure after you put in the new size you click the 'Apply' button just below the image size text boxes before hitting save.
I also agree with the above post that the size you have chosen is really quite small and could also be the issue. As well, PNGs tend to look a lot nicer for most work.
Can you copy the object from Illustrator to Photoshop?
Illustrator's artboard is designed for vector objects, but it sounds like you're doing raster images via Save for Web via Illustrator.
Also Photoshop will show your object as 100% to scale, so zooming won't be an issues.
Also, a side problem - but the default photo viewer for Windows sucks. It will probably show slightly blurry no matter what zoom you're using. Try dropping the image into a browser and view it there.