Error in adding an image to Azure Devops with API POST

I'm trying to add an image in a field in my Azure Devops, but I keep getting this error:

I'm using this code to store it into the text box:

{
    "op": "add",
    "path": "/fields/System.Description",
    "from": null,
    "value": "<div><img src=%22https%3A//dev.azure.com/myorg/mytoken/_apis/wit/attachments/8c339e7d-a25e-4980-93bc-87fa2eaba43e?fileName=dssdfsdfsdf.png%22><br></div>"
}

When I click in that "blank" image, I get a page with this information:

{
    "$id": "1",
    "innerException": null,
    "message": "A potentially dangerous Request.Path value was detected from the client (:).",
    "typeName": "System.Web.HttpException, System.Web",
    "typeKey": "HttpException",
    "errorCode": 0,
    "eventId": 0
}

The API request that I'm doing is:

POST https://dev.azure.com/{organization}/{project}/_apis/wit/attachments?api-version=7.1-preview.3

It does give me a success response, and returns the link that I entered in the <img src= element.

But then the image isn't being shown.

I tried changing the ":" in the img source to an %3A but it doesn't work either.

The rest api is used to add attachment only, cannot image add to work item description field.

POST https://dev.azure.com/{organization}/{project}/_apis/wit/attachments?api-version=7.1-preview.3

With above rest api, you can get the attached image url:

$organization = "ORG"
$project = "PROJECT"
$fileName = "testimage.png"
$personalAccessToken = "YourPAT"
$filePath = "C:\Users\wade\Downloads\testimage.png"   # image file path

$uploadUrl = "https://dev.azure.com/$organization/$project/_apis/wit/attachments?fileName=$fileName&api-version=7.1-preview.3"

$headers = @{
    Authorization = "Basic " + [Convert]::ToBase64String([Text.Encoding]::ASCII.GetBytes(":$personalAccessToken"))
}

$response = Invoke-RestMethod -Uri $uploadUrl -Method Post -Headers $headers -InFile $filePath -ContentType 'application/octet-stream'

$imageUrl = $response.url

Write-Host The imageurl is: $imageUrl

With the image url, you can use rest api Work Items - Update to add image to the work item description field. Change the work item id to yours.

$organization = "ORG"
$project = "Project"
$personalAccessToken = "YourPAT"

$workItemId = "498"        # change to use your work item id
$updateUrl = "https://dev.azure.com/$organization/$project/_apis/wit/workitems/$workItemId"+ "?api-version=7.1-preview.3"

$imageUrl= "your image url get from above rest api"

$description = "<div>add testimage in description<img src='$imageUrl' 'alt=testimage.png'></div>"


$body = @(
    @{
        op = "add"
        path = "/fields/System.Description"
        value = $description
    }
)


$headers = @{
    Authorization = "Basic " + [Convert]::ToBase64String([Text.Encoding]::ASCII.GetBytes(":$personalAccessToken"))
}

Invoke-RestMethod -Uri $updateUrl -Method Patch -Headers $headers -Body (ConvertTo-Json -InputObject $body) -ContentType 'application/json-patch+json'

Image added to the description:

The whole script is below:

$organization = "ORG"
$project = "Project"
$fileName = "testimage.png"
$personalAccessToken = "YourPAT"
$filePath = "C:\Users\wade\Downloads\testimage.png"


$workItemId = "498"

$uploadUrl = "https://dev.azure.com/$organization/$project/_apis/wit/attachments?fileName=$fileName&api-version=7.1-preview.3"


$headers = @{
    Authorization = "Basic " + [Convert]::ToBase64String([Text.Encoding]::ASCII.GetBytes(":$personalAccessToken"))
}

$response = Invoke-RestMethod -Uri $uploadUrl -Method Post -Headers $headers -InFile $filePath -ContentType 'application/octet-stream'

$imageUrl = $response.url

Write-Host The imageurl is: $imageUrl

$description = "<div>add testimage in description<img src='$imageUrl' 'alt=testimage.png'></div>"

$body = @(
    @{
        op = "add"
        path = "/fields/System.Description"
        value = $description
    }
)

Invoke-RestMethod -Uri $updateUrl -Method Patch -Headers $headers -Body (ConvertTo-Json -InputObject $body) -ContentType 'application/json-patch+json'

You can refer to below similar ticket for your reference:

How to add inline image in Azure Devops work item description

pass a valid patch document to update work item using Powershell

Edit:

If your source image is external online, you need to store it firstly, change the attachment code as below:

$organization = "orgname"
$project = "projectname"
$fileName = "testimage.png"
$personalAccessToken = "PAT"

# Define the URL of the image and the path where you want to save it
$imageUrl = "https://s3.amazonaws.com/movidesk-files/D584934F217A52B0230B0870091B7EFA"
$filePath = "C:\Users\wade\Downloads\testimage.png"

# Download the image
Invoke-WebRequest -Uri $imageUrl -OutFile $filePath


$uploadUrl = "https://dev.azure.com/$organization/$project/_apis/wit/attachments?fileName=$fileName&api-version=7.1-preview.3"


$headers = @{
    Authorization = "Basic " + [Convert]::ToBase64String([Text.Encoding]::ASCII.GetBytes(":$personalAccessToken"))
}

$response = Invoke-RestMethod -Uri $uploadUrl -Method Post -Headers $headers -InFile $filePath -ContentType 'application/octet-stream'

$imageUrl = $response.url

Write-Host The imageurl is: $imageUrl