CCNA Lab: Setup A Cisco IOS image To Use In GNS3

Once you finish installing GNS3 and its related components, you have to define the Cisco IOS images for the routers models you'll use in your CCNA lab. The upcoming paragraphs give an idea on the current supported IOS images by GNS3 and how to set up an IOS image on GNS3.
The actual version of GNS3 supports the following Cisco platforms: 1710, 1720, 1721, 1750, 1751, 1760, 2610, 2610XM, 2611, 2611XM, 2620, 2620XM, 2621, 2621XM, 2650XM, 2651XM, 2691, 3620, 3640, 3660, 3725, 3745, and 7200.
Here are the steps you need to follow in order to define the Cisco IOS image for a particular Cisco router platform:
Step 1: Open GNS3 by clicking the Start menu, choosing All Programs, clicking on GNS3, and then click
GNS3.
Step2: In the Edit menu, click on IOS image and hypervisors.
Step 3: Under the IOS Images tab, open the location where your Cisco IOS image is, click on it, and then click on the Open button. The IOS image file will be shown in the IOS image list.
Step 4: In the Platform drop-down list, select the platform that corresponds to your Cisco IOS image file.
Step 5: In the Model drop-down list, select the model corresponding to your IOS file.
Step 6: In the Default RAM field, enter the default RAM value that will be allocated for the current Cisco IOS image.
Step 7: for the first time you use GNS3 on your computer, you cannot set the IDLE PC value because varies from computer to another. However, try to find the best value that works with the actual Cisco IOS image, and then return to the current windows and adjust the IDLE PC setting.
Step 8: Click on the Save button and then click on the Close button.
Keep in mind that in order to use a Cisco IOS images, you must have your own Cisco IOS image to use it with GNS3 because of the licensing requirements.