Lab 6: Reducing Image File Size, Compression and Archiving

Reducing Image File Size

• Create a folder named weblab6 in your folder.
  
• Copy the files mandrill.jpg and open_office_org_logo.bmp into the folder.
• Cropping:
  
• Open mandrill.jpg in the GIMP editor.
• Select the knife (crop and resize) tool.
  
• Select the area that includes only the main facial features. Click the Crop button.
• Right-click the image, move to File and Save As mandrill2.jpg. Note the decrease in file size.
• Scaling:
  
• Open mandrill.jpg again. Right-click the image. Move to the Image menu and click Scale Image.
• Scale to 20% of width and height. Save as mandrill3.jpg . Note the decrease in file size.
• Open open_office_org_logo.bmp. Scale to 500%. Note the pixellation (jagged appearance).
• Save as open_office_org_logo2.bmp. Note the increase in file size.
  
• File Type:
  
• Open open_office_org_logo.bmp again and save as open_office_org_logo.gif . Note the decrease in file size.
  

Compression and Archiving

• Click the K menu, move to Utilities and click Ark.
• Select File, New. Create a file named weblab6.zip.
• Click Action, Add Directory, and type the path of your weblab6 folder. Click OK.
  
• Examine the compressed files in the file list.
  
• Ratio indicates the percent the file was compressed (size - size now) / size.
• Which file type compressed most? Least?
  

E-Mailing as an Attachment

• Send the weblab6.zip file as an e-mail attachment to the lecturer with subject line web lab 6.