I will never claim to be an expert blogger but I have learned a lot over the last year and a half of doing it. One thing that has been the most valuable is how to size my photos so they use up a large amount of my posting space. With Blogger you get just a few options on the size of your photos--small, medium, large, extra large and original size. That drove me nuts because if I chose large they never seemed big enough and if I chose extra large they ran over my posting area. Forget trying original size on a photo that is unedited because it was huge.
Then, I discovered the PERFECT photo size!! I have no idea where I read this and I wish I did so I could give them credit because it's been the best tip I've found for blogging so far.
So, do you want to know the perfect size for most blogs? I bet you do! 550 pixels wide and then you can determine the height. I LOVE this tip!
Here is an example of a picture that is just a regular unsized photo,
setting it to large in the blogger format:
Now, this is the same picture resized to 550 pixels wide and 366 pixels high:
It makes a difference! I always use the "scale photo" option when resizing and that way it just automatically calculates the best height so the photo is not distorted in any way. Any photo editing software will have this as an option.