---
title: ImageInfo
summary: API reference for ImageInfo.
status: draft
owner: SAIF
last_reviewed: 2026-07-24
library: SAIF.Business
reference_type: package
---

# ImageInfo

`ImageInfo` is a public class in `SAIF.Business` that associates a tower record with IFN storage identifiers and exposes helpers for locating and inspecting the underlying image document.

## Purpose
- Stores the tower ID, IFN disk set, IFN ID, and optional image sequence number for an imaged document.
- Resolves UNC server paths, relative paths, and full file paths for IFN-based image storage.
- Loads image metadata from the `image` and `imgsys` tables through the shared `FillBy...` factory methods.
- Determines stored document file types and reads image bytes from disk, optionally under impersonated credentials.

## Context
- Namespace: `SAIF.Business`
- Assembly/package: `SAIF.Business`

## Public members
| Member | Signature | Purpose |
| --- | --- | --- |
| `operator =` | `Public Shared Operator =(x As ImageInfo, y As ImageInfo) As Boolean` | Returns `True` when both instances are `Nothing` or when both instances have the same `TowerID`. |
| `operator <>` | `Public Shared Operator <>(x As ImageInfo, y As ImageInfo) As Boolean` | Returns the negated result of the `=` operator for two `ImageInfo` instances. |
| `ExistsInDb` | `Public ReadOnly Property ExistsInDb As Boolean` | Indicates whether the instance was populated from a matching database row. |
| `ExistsOnDisk` | `Public ReadOnly Property ExistsOnDisk As Boolean` | Checks whether the resolved image file currently exists on disk when IFN values are present. |
| `ImageSeqNum` | `Public ReadOnly Property ImageSeqNum As Decimal` | Returns the associated image sequence number. |
| `TowerID` | `Public ReadOnly Property TowerID As Decimal` | Returns the associated tower ID. |
| `IFNDiskSetID` | `Public ReadOnly Property IFNDiskSetID As Decimal` | Returns the numeric IFN disk-set identifier. |
| `IFNDiskSet` | `Public ReadOnly Property IFNDiskSet As String` | Converts `IFNDiskSetID` into the formatted IFN disk-set string used in IFN text values. |
| `IFNID` | `Public ReadOnly Property IFNID As Long` | Returns the numeric IFN identifier. |
| `IFN` | `Public ReadOnly Property IFN As String` | Returns the combined `IFN: diskset-id` text for the current image. |
| `ImageFullPath` | `Public ReadOnly Property ImageFullPath() As String` | Returns the full UNC path to the image document. |
| `ImageRelativePath` | `Public ReadOnly Property ImageRelativePath() As String` | Returns the relative IFN folder path for the image document. |
| `ImageServerPath` | `Public ReadOnly Property ImageServerPath() As String` | Returns the IFN server UNC and disk-set path for the image document. |
| `Environment` | `Public ReadOnly Property Environment As DevelopmentEnvironment` | Returns the current converted development environment from `AppGlobal.EnvironmentService`. |
| `GetImageFileType` | `Public Function GetImageFileType(Optional creds As SAIFCredentials = Nothing) As String` | Determines the current image file type for this instance's IFN values. |
| `GetImageFullPath` | `Public Function GetImageFullPath(Optional includeFileName As Boolean = True) As String` | Returns the full image path for this instance, optionally omitting the file-name marker. |
| `GetImageRelativePath` | `Public Function GetImageRelativePath(Optional ByVal includeFileName As Boolean = True) As String` | Returns the relative image path for this instance, optionally omitting the file-name marker. |
| `New` | `Public Sub New(towerID As Decimal, ifnDiskSetID As Decimal, ifnID As Long)` | Initializes an `ImageInfo` with tower and IFN values for callers such as PDF services. |
| `New` | `Public Sub New()` | Initializes an empty `ImageInfo`. |
| `FillByImageID` | `Public Shared Function FillByImageID(dpi As IDataPortalInfo, imageSeqNum As Decimal) As ImageInfo` | Loads tower and IFN data for an image sequence number from the `image` and `imgsys` tables. |
| `FillByIFN` | `Public Shared Function FillByIFN(dpi As IDataPortalInfo, IFN As String) As ImageInfo` | Parses an IFN text value and loads the matching image metadata when parsing succeeds. |
| `FillByIFN` | `Public Shared Function FillByIFN(dpi As IDataPortalInfo, IFNDiskSetID As Decimal, IFNID As Long) As ImageInfo` | Loads the most recent image sequence number and tower data for a specific IFN disk set and IFN ID. |
| `FillByTowerID` | `Public Shared Function FillByTowerID(dpi As IDataPortalInfo, towerID As Decimal) As ImageInfo` | Loads IFN data and the most recent image sequence number for a tower record. |
| `ToString` | `Public Overrides Function ToString() As String` | Formats the IFN, tower ID, and optional image sequence number into a display string. |
| `ParseIFN` | `Public Shared Function ParseIFN(ifnText As String, ByRef ifnDiskSet As String, ByRef ifnID As Long) As Boolean` | Parses `IFN:` text into separate disk-set and numeric IFN components. |
| `GetImageFullPath` | `Public Shared Function GetImageFullPath(ifnDiskSet As Decimal, ifnID As Long, Optional includeFileName As Boolean = True) As String` | Builds a full UNC image path from an IFN disk set and IFN ID. |
| `GetImageServerPath` | `Public Shared Function GetImageServerPath(ByVal ifnDiskSetID As Decimal) As String` | Resolves the UNC server and disk-set root for the supplied IFN disk-set identifier. |
| `GetImageRelativePath` | `Public Shared Function GetImageRelativePath(ByVal ifnID As Long, Optional ByVal includeFileName As Boolean = True) As String` | Builds the IFN-based relative folder path and optional file-name marker for an IFN ID. |
| `GetImageFileType` | `Public Shared Function GetImageFileType(ByVal inIFNDiskSetID As Decimal, ByVal inIFNID As Long, Optional creds As SAIFCredentials = Nothing) As String` | Resolves the file path for an IFN pair and then determines the stored document type. |
| `GetImageFileType` | `Public Shared Function GetImageFileType(filePath As String, Optional creds As SAIFCredentials = Nothing) As String` | Reads file header bytes from disk and maps them to SAIF image file-type codes. |
| `ReadAllBytes` | `Public Shared Function ReadAllBytes(filePath As String, Optional creds As SAIFCredentials = Nothing) As Byte()` | Reads the entire image file into memory when the file exists. |

## Behavioral notes
- `ImageFullPath`, `ImageRelativePath`, and `ImageServerPath` all call a private cache routine that recalculates stored paths only when `IFNDiskSetID` or `IFNID` changes.
- `ExistsOnDisk` returns `False` without touching the file system unless both `IFNID` and `IFNDiskSetID` are greater than zero.
- `FillByImageID`, `FillByIFN`, and `FillByTowerID` each return a non-throwing fallback object when no matching row is found.
- `GetImageServerPath` special-cases disk-set prefixes beginning with `387-4` to `\\idmprod\387-4\`; other prefixes are routed to an environment-specific image server.
- `GetImageFileType(filePath, ...)` opens the file, reads the first 69 bytes, and maps stored markers to values such as `TWR`, `TXT`, `JPEG`, `OLDDOC`, `OLDXLS`, `DOC`, `DOCX`, and `XLSX`.

## Constraints and usage notes
- Use the shared `FillBy...` methods when the object must be populated from `image` and `imgsys` table data; the public constructors do not perform database lookups.
- `ParseIFN` expects an IFN pattern shaped like `IFN: <diskset>-<id>` where the disk-set portion contains digits separated by `/`.
- `GetImageFileType` and `ReadAllBytes` optionally impersonate through `SAIFCredentials` before opening files.
- Equality for two populated instances is based on matching `TowerID` values rather than matching image sequence numbers or IFN values.

## Sources
- `Business\SAIF.Business\ImageInfo.vb`