I looked in the User Manual for the Samsung Galaxy Mini GT-S5570. If that is the model you have, you can download it as a pdf file at: http://www.samsung.com/nz/support/model/GT-S5570EGAVNZ-downloads.
That said, I thought about maybe the pictures are automatically getting stored to internal memory instead of the SD card. Yet, it sounds like the Galaxy won't even take pictures without a SD card. Yet, I had a cellphone that still allowed the pictures into internal memory instead of the SD card. Just something to check.
You should not format the SD card on a PC, according to the user manual:
"› Format the memory card
Formatting your memory card on a PC may cause
incompatibilities with your device. Format the memory
card only on the device.
In Idle mode, select → Settings → SD card and phone
storage → Unmount SD card → OK → Format SD card →
Format SD card → Erase everything.
• Your device supports only the FAT file structure for
memory cards. If you insert a card formatted with
a different file structure, your device will ask you to
reformat the memory card."
If you find the Galaxy asks you to reformat the memory card, that is why.
Be sure to remove your sd card using this procedure.
"› Remove the memory card
Before removing a memory card, first unmount it for safe
removal.
1 In Idle mode, select → Settings → SD card and
phone storage → Unmount SD card → OK.
2 Open the cover to the memory card slot on the side of
the device.
3 Push the memory card gently until it disengages from
the device.
4 Pull the memory card out of the memory card slot.
5 Close the cover to the memory card slot. Do not remove a memory card while the device is
transferring or accessing information, as this could
result in loss of data or damage to the memory card
or device."
You probably are already, but just for your info, in case.
Do you have a built in SD card reader on your PC? You should see the Galaxy SD card as a separate removal drive in My Computer on your PC (assuming Windows XP operating system). If not, something might be wrong with your SD card reader.
Alternately, you could try reading the SD card from inside your Galaxy using the USB connector from the Galaxy to the PC. PC software called "Samsung Kies" needed to do this is available for free. See below:
"PC connections
Learn to connect your device to a PC with a PC data cable
in various USB connection modes. By connecting the
device to a PC, you can transfer data to and from your
device directly and use the Samsung Kies program.
› Connect with Samsung Kies
Ensure that Samsung Kies is installed on your PC. You can
download the program from the Samsung website
(www.samsung.com/kies).
1 Using a PC data cable, connect the multifunction jack
on your device to a PC.
Samsung Kies will launch automatically.
If Samsung Kies does not automatically launch,
double-click the Samsung Kies icon on your PC.
2 Copy files from the PC to the phone.
Refer to the Samsung Kies help for more information.
› Connect as a mass storage device
You can connect your device to a PC as a removable disk
and access the file directory. If you insert a memory card
in the device, you can also access the file directory of the
memory card by using the device as a memory card reader.
The file directory of the memory card will appear
as a removable disk, separate from the internal
memory.
1 If you want to transfer files from or to a memory card,
insert a memory card into the device.
2 Using a PC data cable, connect the multifunction jack
on your device to a PC.
3 Open the shortcuts panel.
4 Select USB connected → Connect storage to PC →
OK.
5 Open the folder to view files.
6 Copy files from the PC to the memory card.
7 When you are finished, select Disconnect storage
from PC.
To disconnect the device from the PC, click the
USB device icon on the Windows task bar and
click the option to safely remove the mass storage
device. Then remove the PC data cable from the PC.
Otherwise, you may lose data stored on the memory
card or damage the memory card."
I hope that helps.
Mark