Nice shot and framing here. It does seem a little underexposed and I'm guessing you used a pretty wide F stop. I'd like to have seen a narrower F stop to get the front petal in focus. It's a bit distracting being OOF.

The color is beautiful, and I love the rose's angle.

This shot is nicely done. I really like the colors and how well this fills the frame. I also like how the stem comes in at an angle, rather than straight up into the frame. I agree with Jen, that the dof could use some work. I don't think it necessarily needs to be a larger dof, but it needs to be different. Either large enough to get the whole flower in focus, or small enough to really focus us in on a specific part of the flower. I would actually prefer a smaller dof in this shot, and really focus in on that center group of petals. Also having the petal on the left cut off just barely is a little distracting. Either cut if off more so it doesn't look like it was on accident, or just zoom out a tad more to get it in the shot. I really think you have a nice picture here.

That rose is a beautiful color. Great tight shot. I tried to take a picture of a rose and mine looked horrible - you did a great job!

Thanks for the comments, unfortunately I am still struggling to get my images downsized to less than 600 pixels a side ended up cutting of a petal tip!! Will leave a little more room next time.

You shouldn't have to crop anything to get your dimensions to fit. You can just resize the entire image, this will leave your picture as is, just shrink it down a little smaller. How have you been resizing it? If you have been doing a crop try doing a resize instead.

I usually rough crop before I resize, one of the challenges is the quality of image, I shoot in 'best' ending up with the image size between 1-2 mgb. For the rose I added a 1 pixel border (black) after resizing, then found the image was 122kb! so I chose to recrop rather than resize to make it fit - cutting off the tip of the rose petal.
The final resizing I do ' save as', with options checked, then decrease the quality until I am under the size limit, find that usually ends up around 95 -96% which is where I am losing the sharpness in detail. Any tips welcome

I usually don't do any cropping on my shots. I simply resize to make the longest edge 640 pixels and keep the ratios so the shorter edge automatically adjusts and I put the resolution at 72 ppi, which is all most browsers can really show anyway. Then, if you think you have lost detail, looking at it at 100%, do some sharpening. Always do sharpening after you have resized. Then I save for jpg usually at medium, or 6, quality and it keeps me under. This shot is only 500 on the longest edge, I would be that bumping that up to 640 and dropping your resolution, or the jpg quality, would make it look a little better, but I can't say that for sure unless I actually saw it. Also, make sure you are saving in sRGB mode for you color space, that is what browsers use to render images, if you save it in a different color space it won't look quite right.

I like the picture and the colors of the rose. There are just a couple of spots that are little out of focus and I keep wishing the whole thing was in focus. Just a personal preference though. Still a very nice photo.