Can not send images because of the size limit of the mail attachment? Do not have space to store photos on the SD card?
JPG Optimizer is the best solution for you.
This app will allow you to compress large photos into smaller sized photos with very less or negligible loss in quality.
More, unique ISO Noise Optimization algorithm allows you to reduce image file size with quality enhancement.

Some features of JPG Optimizer:
1. Compress, Resize photos
2. Compress or Resize multiple photos at once
3. Allows you to tune quality of compressed image
4. Unique ISO Noise Optimization algorithm
5. Share and save images as separated JPEGs