I’m not sure about machines running op systems other than windows xp pro but if you use xpp or home, additional apps or drivers aren't necessary to xfer your g1 pics to your computer. Just plug the usb cable that came with your phone into your powered up g1 & any usb port on your up & running pc.
After a few secs your g1 will see the connection & show a new usb icon in the notification bar atop the home screen. Pull down the notification bar & press "USB connected." Then press "Mount." The sd card should then appear on your computer's list of drives (in windows explorer) as some sort of usb device. Click on the “+” next to the newly listed drive/device to view all the folders on your sd card. This will enable xfer, copy, delete etc. for all the files on your sd card using your computer.
Make or select a folder on your computer to xfer your pics to, select the pic files on your sd card & copy away. You can then delete the files off your sd card to free up some space if you like. My g1 stores all my pics (.jpg files) & videos (.3gp files) made with the g1 on the sd card in the "dcim" folder in the "Camera" sub-folder.
When you are finished, you need to “un-mount” the sd card from your computer. In win xp pro click on the “Safely Remove Hardware” icon in the task bar, locate & select the usb device in the hardware device list & click stop. Then select “HTC Android phone” & click stop again. Then pull down the notification list on your g1, press “Turn off USB storage” then press “Turn Off.” Now you can leave your g1 connected & the usb icon will remain in the notification bar & the usb cable will continue charging/powering your g1 or you can disconnect & go. If you want to re-mount the sd card, unplug the g1 from the cable or the cable from your computer then reconnect otherwise your pc will not recognize the g1 when you try to mount the sd card again if it remains connected after un-mounting.
As an alternative, if your pc has an sd card reader, you could remove the card from your g1 after un-mounting it in the sd card settings & then stick it in the reader and use the same copy, paste, delete operations through win explorer to accomplish the same thing.