ipad email not showing images since 16.5 update

On the basis of your description, there are two different functions that may be impacting your Mail client…

1) You may have enabled the Mail Privacy Protection:

Settings > Mail > Privacy Protection > Protect Mail Activity - set to ON

In some circumstances, network connectivity (WiFi or internet) can interfere with this function. When this occurs, you will see the message that you describe - indicating that while you can still receive email, the intended additional protection* is currently unavailable.

(*) You should note that while this function reduces the ability of a sender to track when, or how often, you access the received email - this feature also has a negative impact to your privacy. As all embedded content is loaded in the background, this function confirms that the email address exists. For automatically generated Spam email, this can attract additional unwanted email from advertisers or phishing.

2) Apple’s default Mail settings now initially blocks download of embedded content - whereas iPadOS14 and earlier this behaviour had to be configured if required.

This security measure is intended to inhibit loading of potentially unsafe content - until such time as the recipient has had opportunity to review the email and determine whether or not the received email is from a trusted or expected source. Where images and other content have not been dowloaded, you may see a message at the top of the received email. For example…:

This behaviour has a secondary benefit. When accessing your email over a slow internet connection, the majority of your email messages can be quickly downloaded - without having to wait for bandwidth-hogging download of images and large attachments. This material can be selectively downloaded, if required, after reviewing the body text of the associated email message.

Whilst not recommended, should you wish to change this protective behaviour and automatically download all content, a simple change can be made in your device settings:

Settings > Mail > Privacy Protection > Block All Remote Content - set to OFF

This screenshot shows the relevant setting in its more secure state:

If settings are left is their more secure state, embedded content can be simply loaded if appropriate using the Load All Iimages button:

it is perhaps worthwhile to understand the reasoning for the default behaviour - whereby embedded images are not initially loaded…

By delaying loading of images until the body text is verified by the recipient, potentially malicious content and trackers are not loaded before the recipient has had opportunity to verify that the email is from an expected source or sender - or, for unsolicited email, taken the positive decision to download all content. Most legitimate email has adequate “body” to establish whether of not the email is (a) legitimate and (b) of interest to the sender.

If instead all content is loaded by default, malicious content is given opportunity to run malicious code or attempt a malware exploit. Similarly, images that contain (or are themselves) trackers will notify the actor that the email has been opened. At the very least, the sender of a broadcast phishing email is notified of a “live” mail account and recipient.

Additional supporting info can be found here:

If you see 'Unable to load remote content privately' at the top of an email - Apple Support