Resize And Edit Images On Blogger & Picasa

Here, I have a sample Image with the dimensions 2000px x 2000px Here is the Direct link which is hosted on my Server.
Here I uploaded the image to Blogger and the Blogger Hosted image URL is

http://3.bp.blogspot.com/-z6tcpujc084/UGiN4JhMg_I/AAAAAAAABl0/qpn09SG

In the this url, observe the path before file name. which is Image size s1600 and it is the default blogger dimension.
What does this means, the image dimensions is 1600 on largest side.

What if the Image Widths and Heights are various ?

The first sample image is 2000 pxiels wide on both sides. If i uploaded the image to blogger which is resized to 1600 pixels on both sides. Check the Below Image.

http://3.bp.blogspot.com/-z6tcpujc084/UGiN4JhMg_I/AAAAAAAABl0/qpn09SG

Here another Sample image which dimensions are 2000px x 1200px Here is the Direct Link and is hosted on my Server.
The Blogger Hosted Image is

https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi83LJdYzAv1SJDVDmTJAhqfw0UPy7yL9kEkvTf6EzMY7j4y7RoSTOQxQq7FqrPT_54p86ioYTjuPhzwBvl9EYDF-gZbB8G4TVlOpcJWpjgkIjqgM9dI82tIdjbvw7TtyR6XlqcE5hqXQpW/s1600/sample-2000x1200.jpg

the above image width is 1600 and height is adjusted to corresponding to Original Image size ratio.
Another Example of Sample image which dimensions are 1200px x 2000px  and is hosted on my Server.
The Blogger Hosted Image is

https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgK3u37_Zmaec6Ry6R24xrzDwpp4YmjE-bnYc7UtFjPw9MVVEN39UCVFiRg2GE-YiwBR5pjIDe1juaVK1EcwHIIkMBrPwWAwxmZcgSe7rvw4wxN8t877ltTu4-zcHjfAXBrevcu6Vqhph0c/s1600/sample-1200x2000.jpg

the above image height is 1600 and width is adjusted to corresponding to Original Image size ratio. 

How to Resize my own Images?

Upload the image to Blogger and get the Direct image link. If you want 250px width image, change s1600 to s250 (leading s is important and use any width you want.)

https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi83LJdYzAv1SJDVDmTJAhqfw0UPy7yL9kEkvTf6EzMY7j4y7RoSTOQxQq7FqrPT_54p86ioYTjuPhzwBvl9EYDF-gZbB8G4TVlOpcJWpjgkIjqgM9dI82tIdjbvw7TtyR6XlqcE5hqXQpW/s250/sample-2000x1200.jpg

 And now the image size is 250px width and hight is corresponding ratio to original image.