Mobile Phone Sd Cards

[countrykid]

I have bought a class 10 SanDisk SD Card to replace the much slower Class 4 for my Motorola (Lenovo) Moto G2. I know I need to move anything I need to retain back to the regular internal phone memory (apps, photos etc) and have done this as best as I can.
Here's my query: When selecting Setting>Storage/USB>SD Card it shows that 2.35GB used of 28.42Gb. Apps are 0Gb as all have been switched to internal. Images shows 75.95Mb, Videos 4Kb, Audio 24Kb, Other 17.36Mb, Cached data 0.00. This doesn't add up to the figure given of 2.35Gb????
Regarding Images @ 75.95Mb when I select to show what the content is it shows Camera (just 3 photos of circa 1.5mb each and 4 whatsapp images totalling circa 400Kb and that's it. So again I'm puzzled what else makes up the remaining 70odd Mb
I don't want to remove the existing SD Card before I have safely transferred everything over that I need.
Can anyone help please. Thanks

[TheChair]

Would have made more sense to copy your old SD card to the new one using your PC. After all, the main reason for using an SD card is that you can't fit everything that you want in the internal memory.

[countrykid]

Thanks thechair. I couldn't copy the old sd card via pc as it had been formatted in the phone for use as extra internal memory. I don't have that many apps and no games, music or videos as such, but when it came to some apps being updated, it kept saying insufficient memory. Also I could not add any new apps etc. I'll be using the new sd card the same way. Looking further ahead I may get a phone that has something like 32gb as standard