Why is memory of JPG files copied to SD card on the phone larger than on PC?

[Sri Vinci]

When I copied 50MB worth of pictures into my phone (Lumia 525) I found that the SD card showed about 100MB occupied than what it was previously...I don't understand why?

 

[Microsoftjunkie]

Were you using the WP desktop app? If so, you may have a setting on to compress to save space.

Edit: Sorry, misunderstood.

 

[rhapdog]

It all has to do with how the storage medium is formatted. The SD card in the phone is most likely FAT or exFAT formatted. In your PC it is likely formatted as NTFS.

Also, the block size where it is formatted will make a difference as well. If your SD card formats using 4096 byte blocks, and the PC Hard drive is formatted using 512 byte blocks, then the SD card will use more space to store small files. If you have a bunch of files that are 450 bytes in size, then each file will use a 512 byte block if formatted to that block size, or will use 4096 bytes on a 4096 block size format.
DISCLAIMER: Block sizes and formatting here are not necessarily typical of cards/drives in use today, and are only an example to help you to grasp the concept that lies behind it. That is, the actual sizes may/will vary greatly.

It's like this, when a file occupies part of a block of data, the entire block is considered in use and cannot be reused unless the file is deleted. It is reserved.

Same when I use a flash drive. I have a 128GB flash drive that fills up much faster than my 8GB flash drive. That is, the same files take up much more space on the 128GB drive than on the 8GB drive, simply because of the block allocation sizes of the two flash drives. I believe the 8GB has a 256KB allocation and the 128GB has a 4MB allocation.