In both OBIEE 10g and 11g, custom images need to be placed in 2 folders before use within reports/dashboards.
In OBIEE 10g, images need to be placed in:
(1) $BIHOMEoc4j_bij2eehomeapplicationsanalyticsanalyticsress_oracle10images
Windows directory path example:
C:OracleBIoc4j_bij2eehomeapplicationsanalyticsanalyticsress_oracle10images
Linux directory path example:
/usr/local/OracleBI/oc4j_bi/j2ee/home/applications/analytics/analytics/res/s_oracle10/images
-and-
(2) $BI_HOMEwebappress_oracle10images
Windows directory path example:
C:OracleBIwebappress_oracle10images
Linux directory path example:
/usr/local/OracleBI/web/app/res/s_oracle10/images
In OBIEE 11g, images need to be placed in:
(1) $OBIEE_FMW_HOMEuser_projectsdomainsbifoundation_domainserversbi_server1tmp_WL_useranalytics_11.1.17dezjlwarress_blafpimages
Windows directory path example:
C:obiee11guser_projectsdomainsbifoundation_domainserversAdminServertmp_WL_useranalytics_11.1.1silp1vwarress_blafpimages
Linux directory path example:
/u01/product/middleware/user_projects/domains/bifoundation_domain/servers/bi_server1/tmp/_WL_user/analytics_11.1.1/7dezjl/war/res/s_blafp/images
-and-
(2) $OBIEE_FMW_HOMEOracle_BIbifoundationwebappress_blafpimages
Windows directory path example:
C:obiee11gOracle_BI1bifoundationwebappress_blafpimages
Linux directory path example:
/u01/product/middleware/Oracle_BI1/bifoundation/web/app/res/s_blafp/images
Note: you may also create or use directories at the same level or below the images directories under the s_oracle10 (in 10g) and s_blafp (in 11g) directories, for example, if you wanted to put all your custom images into a separate directory.
Then in Answers / Analysis, you would reference the image as shown below.
Edit the Column Properties:

Then, in the Style tab, within the Cell area, click on the Image object…

Then in the Graphics dialog, select “Custom Image” and enter fmap:images/your_custom_image.jpg.
Note: If your images are in a directory other than the images directory, you need to supply that path, but still starting below s_oracle10 or s_blafp directories.
And set the Image Placement property. Images Left (shows the Image to the left of the column data), Images Right (displays the image to the right of the column data), Images Only (displays the image only – no column data)

If new images were placed into the directories after the last BI Server / Presentation Server restart, you will need to restart the BI Server and Presentation Server for the images to be displayed.