Screen capture. Open the page in a browser and press the Print Screen button, which captures an image of your entire monitor. Then go into Photoshop and create a new canvas which will open at the size of your monitor resolution. Paste and your captured image will appear. Then you’ll be able to crop out the full image that appears sliced in your web design program.
Your other option is to ask the original designer for the work files.
Larry Berman
I’m not sure what amount of image fidelity would be lost if the image was created via a screen capture of the fully assembled image, per Larry’s suggestion, but be aware too that you can manually reassemble the "puzzle". Just create a large enough image canvas in Photoshop for the full assembled image size. Then, open each image slice, select all of it and do a copy. Next, paste that into the blank canvas. Once you’ve done this for all image slices, move the pasted layers around to position them properly. You may need to zoom in on the layer boundaries to ensure the accuracy of the positioning to avoid any gaps. Once complete, flatten the image and save it. This will be much more tedious than Larry’s approach, but should work.
Regards,
Daryl