A large image or photo that is uploaded to your Blogger post will be automatically resized and will be published as a thumbnail (a smaller version of the original image). The resized image will also be not as good in terms of quality when compared to the original image.
Kranthi, of the popular site bloggertricks.com has posted a really informative tutorial on how you can put bigger or larger high-quality images to your Blogger posts:
"Normally, If you upload a large image to blogger(with large thumb size selected), it will automatically resize it and then post it as thumbnail. But, the image quality of the resized image is very poor. So, to make the image look more clean and sharper, this trick will come handy."
Read more HERE...
How to Put Bigger/Larger High-quality Images in Blogger Posts
