Many time we have to customize sap logon page to customer logon page (like image change ) .
Also after upgrade customize logon change to SAP default. We have searched many blogs and note, but did not find simple way to do that. Below method we tried and it worked. Hope this helps others.
1. http://<hostname>:<port>/irj/portal or http://<hostname>:<port>/logon/logonServlet.
2 Do not login
3. Right click the image in the logon page and check the properties , this will provide the information of where there the image is taken from as well as pixel size with image name
4. you should find some thing like this
Address : https://<hostname:port>/logon_ui_resources/layout/branding-image.jpg
5. This information above it basically tell us, from where this image is called upon , so this image is called upon from
/usr/sap/<SID>/J<No.>/j2ee/cluster/apps/sap.com/com.sap.security.core.logon/servlet_jsp/logon_ui_resources/root/layout/
/
6. Replace the sap image with customized image for all the server nodes, pixel size information can be obtained from looking in to the property as mentioned in step 3. Replace the name of your customized image to sap image. Save SAP image for backup.
7. Take a restart and image will be changed.