Can pentax option a20 take a 4gb shdc card - Pentax Optio A20 Digital Camera

easy go to play push menu and find the option transfer , next go to move internal picture to the sd card

It can handle an SHDC also. I have one in mine. Just pick up a MIcro SD card up to 32gb. I picked one up on Amazon for 12 bucks. Works great. Amazon com micro 32 gb sd card 0 15 Memory Cards Cables Accessories...

Here's the manual:
http://www.goaiptek.com/manuals/manual-ahd.pdf

and the SD card is :
SD/MMC card (up to 32GB SDHC)

try using a faster card. SD class 10, not 4. and in the menu, first page, disable all lens correction options, if you're shooting jpeg. these settings do slow you down a lot.

No. The A610 works with MMC and SD cards, 2GB or smaller. It will not work with higher-capacity SDHC cards.

No. The Z650 only takes SD cards, up to 2GB in size. You cannot format an SDHC card in one.

your graphics card shader is low change your graphics card

If software is a problem why not just buy a USB to SD card adapter, and plug your SD card directly into macbook - about $10

Yes, just use the menu system and format your card. In the area when it asks about photo numbering system, just select reset and it should have a new numbering system. Good luck.

Recommended by factory is up to 512 MB, that will work for sure.

It should support up to 2GB card, supporting cards thet have SHDC technology.

Before buying a 2 GB card, I would go to the shop and test it on the camera, so that you are sure it works.

See the forum here :
PowerShot A510 maximum SD card size - Digital Camera Forums