# Before and After Screenshots in Website Change Alerts

Source: PageCrawl.io Blog
URL: https://pagecrawl.io/blog/before-and-after-screenshots-in-website-change-alerts
Published: 14 October, 2026

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A change alert is only as useful as how quickly you can judge it. "The pricing page changed" starts a small chore: open the link, scroll to find the change, and try to remember what the page looked like last week. A text diff is precise about the words, but it flattens the page. You see "$15.49" removed and "$17.99" added, not which plan it belongs to or what else moved around it.

The Before and after attachment puts both versions of the page in the alert itself. Each alert carries one image with two screenshots side by side: the page at the previous recorded change on the left, and the page when this change was found on the right, each labelled with when it was captured. When PageCrawl can find the change on the page, the image zooms in on it and outlines it. It works in Slack, Discord, Microsoft Teams, Telegram and email.

[Image: The Before and after attachment for Netflix's January 2025 US price rise: the old prices outlined in red on the left, the new prices outlined in green on the right]

The image above is the attachment PageCrawl makes for Netflix's US price rise in January 2025, built from two archived copies of its Plans and Pricing page.

### What is the Before and after attachment?

Before and after is an image PageCrawl can attach to your change alerts. It shows a screenshot of the page from the previous recorded change next to a screenshot from the check that found the new one, labelled Before and After with the date and time of each, and zoomed in on the part of the page that changed.

The details that make it quick to read:

- **The change is outlined.** Changed text is outlined in red on the Before side and in green on the After side. A change PageCrawl finds as an area of the page rather than as words, such as a new banner or a swapped image, is outlined in orange on both sides.
- **It zooms to fit the change.** A price or a short line is shown close to full size, and a wide change is shown further out so more of it fits.
- **It stays honest when it cannot tell.** If PageCrawl cannot work out where on the page the change is, the image shows the top of both pages without outlines, rather than pointing at a guess.
- **The dates are yours.** Each side is labelled in your workspace's time zone, and the year is added when the two captures fall in different years.

The Before side is the page as it was at the previous change PageCrawl recorded, not at the last check. On a page that rarely changes, that can be weeks or months earlier, which is the comparison you want: the page as it was the last time something on it changed.

### Why put screenshots in a change alert?

A text diff tells you which words changed. Screenshots show where those words sit on the page and what surrounds them. Seen together in the alert, they answer most questions about a change without opening a browser: which plan got more expensive, whether a banner replaced the main image, or whether a button disappeared.

That matters most on pages where layout carries meaning:

- **Pricing tables.** A number in a diff does not say which plan or column it belongs to. The screenshot does.
- **Product pages.** A "Sold out" badge, a new delivery estimate or a different product photo reads at a glance in a picture.
- **Landing pages and layouts.** A redesigned hero section or a removed sign-up form is easier to see than to read about.
- **Shared channels.** Colleagues reading the alert in Slack or Teams can judge it from the message, without opening PageCrawl.

The text diff stays in the message next to the image, so you keep the exact wording too. The summary and importance are still there as well, so you can decide what deserves a closer look.

### What does a real alert image look like?

It shows two screenshots side by side, each labelled with when it was captured, zoomed in on the change and outlined: old values in red on the left, new values in green on the right. For Netflix's US price rise in January 2025, both sides show the Pricing (US Dollar) list on its Plans and Pricing page, where Standard with ads went from $6.99 to $7.99 a month, Standard from $15.49 to $17.99 and Premium from $22.99 to $24.99. The image at the top of this post is that attachment.

It was built from two Internet Archive copies of the page, one from [20 January 2025](https://web.archive.org/web/20250120130138/https://help.netflix.com/en/node/24926) and one from [22 January 2025](https://web.archive.org/web/20250122123409/https://help.netflix.com/en/node/24926). The rest of the visible page is left untouched for context.

| Plan | 20 January 2025 | 22 January 2025 |
|---|---|---|
| Standard with ads | $6.99 / month | $7.99 / month |
| Standard | $15.49 / month | $17.99 / month |
| Premium | $22.99 / month | $24.99 / month |
| Extra member | $7.99 each / month | $6.99 with ads or $8.99 without ads / month |

The extra member row is a good example of what a picture adds. In a diff, the old and new lines read like an unrelated rewrite. In the image, you can see the extra member price move out of each plan's line onto its own line under the plan, with separate prices with and without ads. You can monitor the live [Netflix Plans and Pricing page](https://help.netflix.com/en/node/24926) the same way.

### How does the image appear in Slack, Discord, Teams, Telegram and email?

Each app shows the same image in its own way. Slack, Discord and Microsoft Teams show it inside the alert, below the summary and the text diff. Telegram sends the alert as a photo, with the alert text as its caption. Email attaches it as a file named before-after.jpg, and the message keeps the text diff.

| App | Where the image appears | To see it full size |
|---|---|---|
| Slack | Inside the alert, below the summary and the diff | Click the image |
| Discord | In the alert's embed | Click the image |
| Microsoft Teams | In the alert card | Click the image to expand it |
| Telegram | As a photo, with the summary and the diff in its caption | Tap the photo |
| Email | As an attachment named before-after.jpg | Open the attachment |

On Telegram, a long diff is shortened to fit the caption, so the photo and the summary always arrive together. In email, the image is usually a file of a few hundred kilobytes, so it does not weigh down an inbox the way a full-page screenshot can.

Note: email alerts leave out all attachments when Changes to show is set to AI summary only, or when the diff is too long to include in full. Chat apps still show the image in both cases.

### How do you turn on Before and after for Slack, Discord, Teams or Telegram?

Open Integrations in your workspace settings, choose Manage on the channel under Notification Channels, set Attachment to Before and after and choose Save Changes. Each app keeps its own setting, so Slack can carry Before and after while Telegram keeps Highlighted changes.

1. Open Settings and choose [Integrations](/app/settings/workspace/integrations) under your workspace.
2. Under Notification Channels, choose Manage on Slack, Discord, Telegram or Microsoft Teams. A channel that is not connected yet shows Setup instead. Connect it first with the [Slack](/help/notifications/article/send-slack-notification-when-changes-detected.md), [Discord](/help/notifications/article/track-website-changes-integrate-with-discord-notifications.md), [Telegram](/help/notifications/article/track-website-changes-integrate-with-telegram-notifications.md) or [Microsoft Teams](/help/notifications/article/send-microsoft-teams-notification-when-changes-detected.md) guide.
3. Open Attachment and choose Before and after.
4. Choose Save Changes.

Slack connects through an [incoming webhook](https://docs.slack.dev/messaging/sending-messages-using-incoming-webhooks/), and Microsoft Teams through a [Workflows webhook](https://support.microsoft.com/en-us/workflows/send-messages-in-teams-using-incoming-webhooks), so the image appears in the channel you picked when you created it. The setting applies to the change alerts that app sends. Scheduled summary reports do not include the Before and after image.

### How do you add it to email alerts?

Open Notifications in your workspace settings, switch on Before and after under Email attachments, and choose Update. The image arrives as a file named before-after.jpg. The Email attachments section appears while email alerts are on, and its screenshot options appear when Screenshots is turned on for your team.

1. Open Settings and choose [Notifications](/app/settings/workspace/notifications) under your workspace.
2. Under Email attachments, switch on Before and after.
3. Choose Update.

You can combine it with the other email attachments. Page screenshot attaches the whole page as it is now, Changes marked in red attaches a screenshot with the changed pixels in red, and Highlighted changes attaches an image of the changed words. The [email notifications guide](/help/notifications/article/email-notifications.md) describes each one.

### Which attachment should you choose?

Choose Before and after when where a change sits on the page matters, as on pricing tables, product pages and layouts. Choose Highlighted changes, the recommended option, when the exact words matter most, as on terms and policies. Choose Page screenshot when you want the whole page as it looks now.

| Attachment | What it shows | Best for |
|---|---|---|
| Before and after | The page before and after the change, side by side, zoomed in on it | Prices, product pages, layout and image changes |
| Highlighted changes | An image of what changed, with removed and added words highlighted | Terms, policies and long text where the wording matters |
| Page screenshot | A full-page screenshot of the latest capture | Seeing the whole page as it is now |
| Text file (Telegram and email) | The page's captured text as a file | Keeping or searching the full text |
| Changes marked in red (email only) | A screenshot with the changed pixels in red | Spotting small visual changes across a page |

The choice is per app, and you can change it at any time. For example, you can send Before and after to Slack, where the team triages changes, and keep Highlighted changes on Telegram for reading on a phone.

### What does Before and after need to work?

It needs a screenshot on both sides of the change. Screenshots must be on for your team and for the monitor, and there must be an earlier recorded check of the page to compare with. When either screenshot is missing, the alert still goes out with its summary and text diff, just without the image.

- **Screenshots on.** Turn on Screenshots in your team's Active Features, and Full Page Screenshots in the monitor's Crawling Preferences.
- **An earlier capture.** There must be an earlier recorded check of the page with its screenshot. A monitor's very first capture has nothing to compare with.
- **A web page.** Files such as PDFs and monitors that use the Fast engine do not take screenshots.
- **A kept screenshot.** If the earlier change's screenshot is no longer kept under your plan's history, there is no Before side to show.

Alerts arrive when a check detects the change, and checks run as often as every 2 minutes depending on your plan. The image is part of that same alert, so you do not wait for a separate message.

### Does it work for price, text and visual monitors?

Yes. For a changed price, number or line of text, PageCrawl finds those words on both screenshots and outlines them in red and green. For a visual monitor, it outlines the changed area in orange. When it cannot place the change, it shows the top of both pages, without outlines.

That covers most of what people monitor: price and stock values, full-page text, specific sections, feeds and visual areas. The outline follows the change the alert is about, found from the alert's own changed words, so a rotating banner elsewhere on the page does not pull the focus away from a price change. If you track several things on one page, the image focuses on the part of the page that holds the changes in this alert. For pages where the look is the whole point, the guide to [visual regression monitoring](/blog/visual-regression-monitoring-detect-ui-changes) covers setting up visual checks.

### Getting started

Pick a monitor where the look of the page matters as much as the words, such as a competitor's pricing page or a product page you buy from. Set Before and after on the channel your team reads, wait for the next change, and judge it from the alert. If you do not have an account yet, you can [create one for free](/app/auth/register) and add your first page in a couple of minutes.

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