Blurry images are usually a result of over-compressed images. There are a few things you can do to prevent this from happening in the upload image section, as shown below:
1. Select "Do not resize"
2. Uncheck "Optimize JPEGs to"
Note: if you images are still blurry, you may need to see if your source image is blurry. If it is, then you may need to correct the image on your computer, and then re-upload. If it is not blurry, then you may need to change the file type, or increase the image size, and then re-upload.
For instructions on how to get to upload images, please visit the following link:
How do I upload images using the e-Store?