There are two options with regards to uploading survey logos - Using a single (same) logo for all your surveys or Using survey-specific logos.
The file you upload must be a .jpg/.jpeg or .png file
The file should be a size of 600 x 90 pixels
1) To Upload the Single (Same) Logo for all your campaigns - use the Configure (All Surveys) option -> Upload Logo Section -> Browse to upload a Logo.
Note: The Logo you upload here will be automatically updated for all your campaigns that do not have a survey-specific logo configuration setup. If you have a survey-specific configuration setup then this setting will not take overwrite that. Please do not attempt to use the general 'Configure (All Survey) Logo' option in order to edit the logo for just one individual survey!
2) To Upload on a Survey Specific Logo - If you have multiple surveys and want them to have different logos you can do so. Go to the Survey group you wish to upload a specific logo to Choose a survey page -> Add the Logo widget -> Browse to upload a Logo. You will need to do the same for every page of the survey in that group.
Based on the above choice - Clicking the Upload Survey Logo option will open the File Uploader. Click on the Upload option:
Select the correct file from your computer's folder, open it into the File Uploader, and double-click it to add to the survey. Please note: your banner should be 600px in width and max 90px in height. If you upload a banner that is higher than 90px, the system will reduce the size of the banner as a whole in order to make it fit. This will result in your banner being narrower than intended.
Click here to get a full overview on Editing a Survey