If you refer to the Golden Rules, you will see that Number 1 states that all your site material (pages, images etc. must be in a single folder - the 'site folder'. One thing that is critical when using different computers to edit your site - and using removeable media (USB sticks) is that your site editing software (Kompozer) 'knows' where the site folder is, otherwise any changes, particularly new links and images added
So, when starting a new session in Kompozer, you should always 're-target' an existing site by using the 'Edit Site' button as per the Step by Step below:
If you are opening your site for the first time on another PC or Mac, you should repeat the first action in the 'Step 2' page: Click on the 'Edit Sites' icon or button (arrowed).
If your site is save on a USB stick and you are returning to a PC or Mac to edit it again. You may see your site name in the list in Site Manager. Click on it and then click on the 'Edit Sites' button.
You'll get the 'Publish Settings' dialogue box just as you did when you first set up the site.
If you are editing for the first time on a new PC, enter a site name at 1 then use the 'Select Directory' button at 2 to go and find your site folder (on the PC/Mac or USB stick). Select it and OK back to this dialogue.
Step 4 - Finishing the targetting
If editing for the first time (i.e. you have put a site name in the entry box at 1 above) you will need to click the 'New Site' button to ensure it is added to the site list in the the 'Publishing sites' box.
If editing again on the same PC/Mac all you have to do is OK to return to Kompozer and start opening and editing your pages.