To generate a thumbnail the full URL should look like this:
https:\/\/tenant.sharepoint.com\/sites\/sitename\/_layouts\/15\/getpreview.ashx?path=https:\/\/tenant.sharepoint.com\/sites\/sitename\/SitePages\/Nederland.aspx<\/a><\/p>\n\n\n\n
Or the thumbnail can be retrieved from another location eg the root The guid parameters are actually three parameters. Or it can be retrieved from another location eg the root Recently an issue arose in which no thumbnails were displayed on a page. Once\nan image is added to the page or the thumbnail of the page is set manually, a\nfolder is generated in the Site Assets library to store the image. When a\nspecial character is used like in the name Belgi\u00eb the folder name gets encoded\nto ‘BelgC3AB’.<\/p>\n\n\n\n As long as the preview handler is used to get the thumbnail within the site the page is stored, the path parameter is working just fine and as expected, but when this thumbnail will be approached from another site it can’t be found and an error (404 Not found) is thrown.<\/p>\n\n\n\n Usage within the site the page is stored results in the preview of the thumbnail: Approach from another site eg the root results in a 404 Not found: To\nbe sure the getpreview handler can generate the thumbnails of a file at all\ntimes use the guid parameters instead of the path parameter.<\/p>\n","protected":false},"excerpt":{"rendered":" Thumbnails for pages in SharePoint Online are generated using the getpreview handler. Using this handler predefined image formats can be used using the ‘resolution’ URL parameter. When this parameter isn’t specified resolution 0 is used: fixed width of 300px. Besides … Read More »<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[39,41],"tags":[37,46],"class_list":["post-2792","post","type-post","status-publish","format-standard","hentry","category-office-365","category-sharepoint","tag-office365","tag-sharepoint"],"_links":{"self":[{"href":"https:\/\/www.itidea.nl\/index.php\/wp-json\/wp\/v2\/posts\/2792","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.itidea.nl\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.itidea.nl\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.itidea.nl\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.itidea.nl\/index.php\/wp-json\/wp\/v2\/comments?post=2792"}],"version-history":[{"count":3,"href":"https:\/\/www.itidea.nl\/index.php\/wp-json\/wp\/v2\/posts\/2792\/revisions"}],"predecessor-version":[{"id":2799,"href":"https:\/\/www.itidea.nl\/index.php\/wp-json\/wp\/v2\/posts\/2792\/revisions\/2799"}],"wp:attachment":[{"href":"https:\/\/www.itidea.nl\/index.php\/wp-json\/wp\/v2\/media?parent=2792"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.itidea.nl\/index.php\/wp-json\/wp\/v2\/categories?post=2792"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.itidea.nl\/index.php\/wp-json\/wp\/v2\/tags?post=2792"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
https:\/\/tenant.sharepoint.com\/_layouts\/15\/getpreview.ashx?path=https:\/\/tenant.sharepoint.com\/sites\/sitename\/SitePages\/Nederland.aspx<\/a><\/p>\n\n\n\n Guid parameters <\/h4>\n\n\n\n
guidSite – the guid of the site collection without the curly brackets
guidWeb – the guid of the web without the curly brackets
guidFile – the guid of the file
https:\/\/tenant.sharepoint.com\/sites\/sitename\/_layouts\/15\/getpreview.ashx?guidSite=e1420f3c716e42c6b6f0f09961dafb87&<\/a>
guidWeb=4131dd01c11b4fcba9b2cdafcca38dbf&<\/a>
guidFile=7711f989664e4bc080161ae4bbabba84<\/a><\/p>\n\n\n\n
https:\/\/tenant.sharepoint.com\/_layouts\/15\/getpreview.ashx?guidSite=e1420f3c716e42c6b6f0f09961dafb87&<\/a>
guidWeb=4131dd01c11b4fcba9b2cdafcca38dbf&<\/a>
guidFile=7711f989664e4bc080161ae4bbabba84<\/a><\/p>\n\n\n\n The inconvenience <\/h4>\n\n\n\n
After some investigation it seemed that special characters in the URL of the page are preventing SharePoint from finding the thumbnail when using the path parameter.
Creating a page using the UI providing the title ‘Belgi\u00eb’ results in a URL of belgi\u00eb.aspx. <\/p>\n\n\n\n![\"\"](\"https:\/\/www.itidea.nl\/wp-content\/uploads\/2019\/10\/1-inconvenient-getpreview-handler.png\")
![\"\"](\"https:\/\/www.itidea.nl\/wp-content\/uploads\/2019\/10\/2-inconvenient-getpreview-handler.png\")
https:\/\/tenant.sharepoint.com\/sites\/sitename\/_layouts\/15\/getpreview.ashx?path=https:\/\/tenant.sharepoint.com\/sites\/sitename\/SitePages\/Belgi\u00eb.aspx<\/a><\/p>\n\n\n\n![\"\"](\"https:\/\/www.itidea.nl\/wp-content\/uploads\/2019\/10\/3-inconvenient-getpreview-handler-1024x301.png\")
https:\/\/tenant.sharepoint.com\/_layouts\/15\/getpreview.ashx?path=https:\/\/tenant.sharepoint.com\/sites\/sitename\/SitePages\/Belgi\u00eb.aspx<\/a><\/p>\n\n\n\n![\"\"](\"https:\/\/www.itidea.nl\/wp-content\/uploads\/2019\/10\/4-inconvenient-getpreview-handler.png\")
Summary<\/h2>\n\n\n\n